GRAILS - a web service client using a client certificate

I am trying to write a web service test and it needs to connect to the web service using a client certificate. I have already set up a server that accepts client certificates, and it works correctly when using the .NET client application. The client certificate works as an authentication mechanism along with the spring security plugin, so I need a way to write a client that can use my user certificate when executing the request.

Now I am trying to write an integration test to test this service, but I can not find any sense in attaching a client certificate when executing the request. I ran wsclient for groovy, ws-lite for groovy and even cxf for java. Not lucky yet.

Is there a way I can attach my own client certificate to a web service client request?