Appending content to dynamic variables a uri

Ok, I asked this before but I never received a solution for it. I have a web/app server that is returning dynamic uri variables and I need to append that.

 

 

For example:

 

Request comes in from the client as

 

http://www.company.com/companyb2c/b2c/in.do?shop=GL-L0

 

 

The web/app server returns a 302 with

 

http://www.company.com/companyb2c/b2c/in.do?shop=GL-L0&Product=26537

 

 

The "Product=26537" is vital and is dynamic. The number changes with each individual request for information. We need for the F5 to append this by adding "&login=true" after the number. So the full url should be formatted to be:

 

 

http://www.company.com/companyb2c/b2c/in.do?shop=GL-L0&Product=26537&login=true

 

 

I remembered there was a way to tell the parser in iRules to count past a certain point but I cannot find it in the iRule keywords.

 

 

Any ideas?