The xml corrupt my Base 64 string when i set it as attribute in flex

[Immegixeplemn]

I convert an image byte array into \[code\]base64\[/code\] string, it successfully converted and if i convert it back into byte array and assign to any image as source work fine.The Problem,If i try to set the same \[code\]base64\[/code\] string as an attribute of an XML that i am locally created for saving purpose it disturb or corrupt my base64 string before send to server.any help ?