SSL unencrypt/reencrypt after looking at header

Excellent, thank you.

The rule is accepted, but when it is actioned, I get the following error in the logs:

TCL error: Rule Test-4 HTTP_REQUEST - cant use 
non-numeric string as operand of ! while executing if 
{ not [HTTP::uri] starts_with /exchange/ || 
[HTTP::uri] starts_with /exchweb/ } { pool content log 
local0.test4-1 } else { set disable 0...

The rule i'm trying to use is:

when HTTP_REQUEST {
set disable 1
if { not [HTTP::uri] starts_with "/exchange/" || [HTTP::uri] starts_with "/exchweb/" }
{
pool UAT-content
log local0."test4-1"
} else {
set disable 0
pool OWA-Pool
log local0."test4-2"
}
}
when SERVER_CONNECTED {
if { $disable == 1 }{
SSL::disable
log local0."nossl"
}
}

Reason for this, is that our MS exchange servers have to use SSL, whereas our Apache can't.. (don't ask me why..)

Any help would be much appreciated!!