can you give more details on what you need?
Do you need to store a QVD with a specific name based on a varialbe?
If you need something like this, you can use $ (dollar) expansion, like below:
set vName = Test;
'A' as Test
store tmp into $(vName).qvd (qvd);
This will store a QVD named Test.qvd into the same folder where you save the QVW with the above code.
Most operations will use the $ expansion when you need to get values from a variable.