Limit download speed via Irule based on SOAP action in body of request?

[MW1]

All, I have been asked if it is possible to limit downloads speed from a web site behind an F5 pair on a specific URI and inspecting the body of the request to match the specific action "downloadcog"

    

    
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I have seen irules to limit the speed based on the URI but not request content - is this possible?

thanks