According to John Michael Black:

I remember reading in an older version's GUIDE that functions returning strings would not work. Was this corrected with 2.7.2?

Yes. Peter e-mail: peter.gerwinski@uni-essen.de home address: D\"usseldorfer Str. 35, 45145 Essen, Germany WWW: http://agnes.dida.physik.uni-essen.de/~peter/