Admin tab translation

[muirch]

Made a module with admin tab.
Made a translation file at AdminTranslations back office page for my tab file and module front-office.
Got php file with translation.
Works perfect for front office.
In back office tab file calling somethink like this:

echo $this->l('Total paid since registration:')

but it shows "Total paid since registration:", not a translated text. None of phrases are translated. Back Office switched to the language I need.
How I can solve this problem?

[muirch]

Still no sulution((