Hi Vincent,
As explained in your other post you can achieve this http://scn.sap.com/thread/3643000
Well if you insist to have label and value to be dynamic follow below.
Instead of 2 labels designed on the form and 2 text fields data to be sourced from your program.
Have 4 fields on the form, 2 for labels and 2 for values.
now in your report program, based on user's log on language populate your labels and value.
Cheers,
Sai