iRule to check for a post body

Thank you very much for working on my iRule. However I have apparently figured out another way - meaning reading off of the payload in the HTTP_REQUEST itself. The following is the iRule. This works out well for me.

when HTTP_REQUEST {
    Send the data using local7 facility <190>
    if { not ([HTTP::cookie exists SITESERVER] ) } {
        set F2C "[string range [AES::key 128] 15 end][string range [AES::key 128] 15 end]"
        HTTP::cookie insert name "F2C" value $F2C
    }
    set cookie [HTTP::header cookie]
    HSL::send [HSL::open -proto UDP -pool syslog_server_pool_1] "<190> [IP::client_addr] \[[clock format [clock seconds] -format "%d/%b/%Y:%H:%M:%S %z"]\] --[IP::local_addr]--NW--80--P2--[URI::path [HTTP::uri]][URI::basename [HTTP::uri]]--QS=[HTTP::query]--C=[HTTP::header cookie]--UA=[HTTP::header User-Agent]--CT=[HTTP::header "Content-type"]"

    if { [HTTP::uri] starts_with "/airlines/landingServlet" and [HTTP::method] eq "POST" } {
        set payload [HTTP::payload]
        set refid "unknown"
        set refclickid "unknown"
        foreach x [split [string tolower $payload] "&"] {
            if { $x starts_with "refid=" } {
                set refid [lindex [split $x "="] 1]
            } 
            if { $x starts_with "refclickid=" } {
                set refclickid [lindex [split $x "="] 1]
            }   
        }
        HSL::send [HSL::open -proto UDP -pool syslog_server_pool_1] "<190> [IP::client_addr] \[[clock format [clock seconds] -format "%d/%b/%Y:%H:%M:%S %z"]\] --[IP::local_addr]--NW--80--P2--pbrefid=$refid--pbrefclickid=$refclickid--C=[HTTP::header cookie]"
        unset payload
    }
}

when HTTP_RESPONSE { 
    if { [info exists F2C] and $F2C ne ""} {
        HTTP::cookie insert name "F2C" value $F2C
        HTTP::cookie expires F2C 630720000
        unset -nocomplain F2C
    }

}