Can anybody help to find exact module i want to translate webmail interface for IMAP users?
Thanks
Howdy,
This thread on general Webmin translations might help:
http://www.virtualmin.com/node/10314
I suspect translating Usermin is going to be quite similar.
If you run into any trouble, just yell, and if I can’t help you, I’ll see if Joe or Jamie can assist 
-Eric