[TYPO3-english] cl_alphabeticalindex: how to localize with utf-8?

[Stephan Bernhard]

hi list

i'm using EXT cl_alphabeticalindex in a german website (utf-8) where the 
umlaut Ü is one of the first characters in several websites.

there are also pages which begin with U.

but all pages are only visible under Ü.
the character U seems to be empty.

the URL shows as follows:

http://mywebsite/?tx_clalphabeticalindex_pi1[achar]=Ü

does anyone know how to change this behavior of the EXT (version 0.1.3)?

thanks for any advice

stephan