how do i change my default pool in a Virtual Server (BigIP LTM)

!/usr/bin/perl
----------------------------------------------------------------------------
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 Software Development Kit for iControl"; you may not use this file except in
 compliance with the License. The License is included in the iControl
 Software Development Kit.
 Software distributed under the License is distributed on an "AS IS"
 basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
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 The Initial Developer of the Original Code is F5 Networks,
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 Inc. All Rights Reserved.  iControl (TM) is a registered trademark of F5 Networks, Inc.
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 License, indicate your decision by deleting the provisions above and
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----------------------------------------------------------------------------
use SOAP::Lite + trace => qw(method debug);
use SOAP::Lite;
use MIME::Base64;
----------------------------------------------------------------------------
 Validate Arguments
----------------------------------------------------------------------------
my $sHost = $ARGV[0];
my $sPort = $ARGV[1];
my $sUID = $ARGV[2];
my $sPWD = $ARGV[3];
my $sVirtual = $ARGV[4];
my $sPool = $ARGV[5];
my $sProtocol = "https";
if ( ("80" eq $sPort) or ("8080" eq $sPort) )
{
$sProtocol = "http";
}
if ( ($sHost eq "") or ($sPort eq "") or ($sUID eq "") or ($sPWD eq "") )
{
die ("Usage: SetVirtualDefaultPool.pl host port uid pwd virtual_name pool_name\n");
}
----------------------------------------------------------------------------
 Transport Information
----------------------------------------------------------------------------
sub SOAP::Transport::HTTP::Client::get_basic_credentials
{
return "$sUID" => "$sPWD";
}
$VirtualServer = SOAP::Lite
-> uri('urn:iControl:LocalLB/VirtualServer')
-> proxy("$sProtocol://$sHost:$sPort/iControl/iControlPortal.cgi");
eval { $VirtualServer->transport->http_request->header
(
'Authorization' => 
'Basic ' . MIME::Base64::encode("$sUID:$sPWD", '')
); };
$Pool = SOAP::Lite
-> uri('urn:iControl:LocalLB/Pool')
-> proxy("$sProtocol://$sHost:$sPort/iControl/iControlPortal.cgi");
eval { $Pool->transport->http_request->header
(
'Authorization' => 
'Basic ' . MIME::Base64::encode("$sUID:$sPWD", '')
); };
if ( $sVirtual eq "" )
{
&getVirtualList();
}
elsif ( $sPool eq "" )
{
&getDefaultPool($sVirtual);
&getPoolList();
}
else
{
setDefaultPool($sVirtual, $sPool)
}
----------------------------------------------------------------------------
 sub getVirtualList()
----------------------------------------------------------------------------
sub getVirtualList()
{
$soapResponse = $VirtualServer->get_list();
&checkResponse($soapResponse);
@vs_list = @{$soapResponse->result};
print "Available Virtual Servers:\n";
foreach $vs (@vs_list)
{
print "  $vs\n";
}
}
----------------------------------------------------------------------------
 sub getPoolList()
----------------------------------------------------------------------------
sub getPoolList()
{
$soapResponse = $Pool->get_list();
&checkResponse($soapResponse);
@pool_list = @{$soapResponse->result};
print "Available Pools:\n";
foreach $pool (@pool_list)
{
print "  $pool\n";
}
}
----------------------------------------------------------------------------
 sub getDefaultPool()
----------------------------------------------------------------------------
sub getDefaultPool()
{
my ($virtual_name) = (@_);
$soapResponse = $VirtualServer->get_default_pool_name
(
SOAP::Data->name(virtual_servers => [$virtual_name])
);
&checkResponse($soapResponse);
@pool_list = @{$soapResponse->result};
$def_pool = @pool_list[0];
print "Virtual Server '$virtual_name' default pool: $def_pool\n";
}
----------------------------------------------------------------------------
 sub setDefaultPool()
----------------------------------------------------------------------------
sub setDefaultPool()
{
my ($virtual_name, $pool_name) = (@_);
$soapResponse = $VirtualServer->set_default_pool_name
(
SOAP::Data->name(virtual_servers => [$virtual_name]),
SOAP::Data->name(default_pools => [$pool_name])
);
&checkResponse($soapResponse);
print "Virtual Server '$virtual_name' default pool changed to '$pool_name'\n";
}
----------------------------------------------------------------------------
 checkResponse
----------------------------------------------------------------------------
sub checkResponse()
{
my ($soapResponse) = (@_);
if ( $soapResponse->fault )
{
print $soapResponse->faultcode, " ", $soapResponse->faultstring, "\n";
exit();
}
}