Ready API Coverage Option

I have some test suites for my API's.

I want to derive the coverage for my tests and I am planning to use the built-in "Contract Coverage" option in Ready API/Soap UI NG Pro.

But the problem is, we don't have the WADL file for our API's and because of this I have Used "Http Request" for my tests instead of "Rest Request".

So anyone of you have any experience in generating coverage reports without a WADL file and by using "Http Requests"?

Thanks,

Linkesh