Add Parameter to request from Screen actions

[Amit Shinde]

Hello Everyone,
          Heres what I am trying to do. I pass a parameter from a URL which
calls a Screen. Now I want to add one more parameter with a different name
to the request in the actions section of the screen.

        Heres the address -

        
http://localhost/xyz/control/additem/~category_id=0200/~add_product_id=DEMO
_PRODUCT_04/~quantity=1/

        I want to add product_id in the request but I cant add it in the above 
URL
else it would have looked like
http://localhost/xyz/control/additem/~category_id=0200/~add_product_id=DEMO_
PRODUCT_04/~quantity=1/~product_id=DEMO_PRODUCT_04

        I tried this but it didnt work -
        <section>
            <actions>
                <set field="parameters.product_id"
from-field="parameters.add_product_id"/>
                ....
        </actions>
         <section>

        Is it possible to add product_id programmatically in the parameters map?

        Any inputs would be appreciated.

Thanks in advance,

Amit Shinde