translation for marketpress

I re come back with another question on marketpress.

I tried to search on forum but i found no answer.

I would like to translate marketpress so i see a mo and po files in languages folder. I translated po file and updated mo file and uploaded this file in the same folder.

But it don't work, so i think there is something to activate in on file but i don't know what file.
Can seomeone explain me what to do ?