Change fastL4 profile in iRule

Hi,

Is it possible to change which fastL4 profile you are using from within an iRule?

My situation is that I need to have an indefinite idle timeout on connections from certain ip addresses, ideally I would modify IP::idle_timeout in the iRule; but there is no valid IP::idle_timeout that will set indefinite. To check if it was possible to set indefinite from within an iRule I changed the fastL4 profile to have indefinite idle timeout then logged the value of IP::idle_timeout

when CLIENT_ACCEPTED {
    if { [IP::addr [IP::client_addr] equals 10.1.1.1] } {
      log local0. "original timeout: [IP::idle_timeout]"
    }
}

This resulted in log lines

CLIENT_ACCEPTED: original timeout: -1

I tried to set this value from within my iRule


<pre class="prettyprint lang-tcl">`when CLIENT_ACCEPTED {
    if { [IP::addr [IP::client_addr] equals 10.1.1.1] } {
      log local0. "original timeout: [IP::idle_timeout]"
      IP::idle_timeout -1
      log local0. "modified timeout: [IP::idle_timeout]"
    }
}

However this produced the following output

 - invalid timeout value (line 1) invoked from within "IP::idle_timeout -1"

So my next thought was to create multiple fastL4 profiles and one of them can have indefinite timeouts, then I can switch to this profile from within my iRule for the connections that I need an indefinite timeout on. Problem being I cannot see a way to change profile from within an iRule.

Any ideas?