How to get the "Mapped User ID" value from the portal into webdynpro abap application

Hi Experts,

   In our system the "Portal" login is different from the ECC login. So, we maintain the ECC login in the "Mapped User ID" property (User administration --> User Mapping) .

I have created an Iview for the webdynpro abap application and was able to read the portal login using the applicaiton paramter "USERID=<User.LogonUid>".

Can we read the "Mapped User ID" with the help of any application parameter? If yes, please provide me with the name of the application parameter.

Attached is the screen shot of the same.

Thanks

Sujata