Hi Hans, hi Simon! First of all THANKS a lot for both of you for helpful hints and sugestions. After many tests and experiments I decided to use construction: \def\XMLsynonym#1#2{% \letcsnamecsname\csname\@@XMLelement:#1/\endcsname\csname\@@XMLelement:#2/\e ndcsname \letcsnamecsname\csname\@@XMLelement:#1\endcsname\csname\@@XMLelement:#2\end csname \letcsnamecsname\csname\@@XMLelement:/#1\endcsname\csname\@@XMLelement:/#2\e ndcsname} It works ok and suits me best since I (almost) understand HOW it works :) Using constructions which I don't understand makes me a little bit frustrated. I'll do my best to understand other constructions as well. Thanks a lot, Pawe/l