Using dynamic command-line arguments

Hi everyone,

I have added a new RemoteApp, which I have to run dynamically according to specific parameters for each user.
I have created a text file for each user,and placed it on \\server\UserArguments , and each text file's name is a different username.

So I have chose the option under Command line Arguments : Always use the following command-line arguments:

\\server\UserArguments\%username%.txt 

But it didn't work. I have also tried to put \\server\UserArguments\john.txtbut it didn't work as well. When I put the arguments I wrote in text file, it worked perfect. 

Any help would be appreciated.

Thanks a lot:)