How to Create a Project Site from a Template

I have created a Project Site through PSI Service using the Create Project From Template and Queue Publish methods.The Project plan is created perfectly but the Project Site created is always a Default Site . The Site Template associated in the EPT is not getting me the required site .

After Searching I knew that I have to Update the EPT to get the required site .How can I update the EPT ???

Any help would by highly appreciated!!!!

Thanks :)