xterm does not recognize CSI / ESC[

Hi all,

I try to use my xterm from SUSE 11.1 as vt100/200 emulator. Problem is that my application sends the CSI as 8bit (0x9b) instead of the ESC+[ commands. With the default settings, xterm doesn't recognize this character as CSI, but prints an inverted question mark

CSI works when I disable utf8 with "xterm +u8", but then other things (like switching to line drawing) don't work.

Has anybody an idea what might be going on?

Til