Project Event and request content with evaluated properties

Hey,

I'm trying to run a Groovy script in the project level events (requestfilter.FilterRequests) and I need the fully evaluated content/body of my request to calculate a hash on the content. The problem is my request uses properties so If I use request.requestcontent I get the content un processed e.g.

"bodyColor":"{$myProperty}". however by the time this is sent out it is of course processed and the server hashes "bodyColor":"blue".

Anyone have an idea of a property or method in the context of requestfilter.FilterRequests that has the request content with values already assigned to properties?

thanks,

dar