[xml] xmlEncodeSpecialChars problem

[oliverst online de]

I have a problem, that I changed from my own encoding function to xmlEncodeEntitiesReentrant and suddenly 
apostrophs (') appeared in my attributes. So I tried xmlEncodeSpecialChars and they still were present. Same 
problem with the quotes ("), but then found out xmlEncodeSpecialChars does that. But now I have the problem, 
that nothing works anymore, because the apostroph still isn't encoded. Judging from the function descrption I 
assume, but both should be the same (differing in the encoding of quote (")) and should encode *all* the 
problematic characters, which (') is one of. Is there a reason, why it isn't concerted?