Turning characters into html entities breaks velocity code

When editing a document in the WYSIWYG editor, characters like " and & are turned into " and &. This is ok for normal text, but breaks macros.

#set($var = "a string")
becomes
#set($var = "a string")

#if($a && $b)
becomes
#if($a && $b)

This raises:
org.apache.velocity.exception.ParseErrorException: Lexical error: org.apache.velocity.runtime.parser.TokenMgrError: Lexical error at line 7, column 15. Encountered: "q" (113), after : "&"