[Plugin: Worpress Mobile Pack] Translate some things

Hello,

I am trying translate WordPress Mobile Pack in a spanish version, i would like translate words like: Recent Posts, By, On, designed by, powered by and some others english words.

I tried edit footer.php in plugin folder and change the words: designed by and powered by, then i uploaded the file and didn’t work :(. I would like do a spanish translation but i dunno what files must i edit to translate correctly, could u show me what i must do?

Thank u very much

Víctor