Subtitles in AVI container - stream names

Hi,
thanks a lot for the free BSplayer that supports subtitles multiplexed in AVI container (with AVI-Mux GUI). But opposite to the audio streams, where the names are shown correctly by BSplayer when I want to switch the stream beeing played, the subtitles only show Sub 1, Sub 2, etc. option.

Can someone please let me know what I am doing wrong? I believe that I name the sub streams correctly in the AVI-Mux GUI as well as the audio streams which work all right.

Thank you.