Send a email with a attachment (binary file)

Hi experts.

How I can send a email with a attachment (a zip file for instance)? This file I receve from another module as base64 (into a xml) and I want send it in a e-mail.

I tryed do like as this http://scn.sap.com/people/stefan.grube/blog/2007/04/17/xi-mail-adapter-an-approach-for-sending-emails-with-attachment-with-help-of-java-mapping but in the email arrive a attachment as text file.

Can somebody helpme?

Thanks!