Trigger on a single rs232 character

[handyguy]

Hi,
I am trying to trigger on a single key press of the DTE (my pc serial output port) and show the pattern on the oscilloscope. So far i can only see hits whiz by when I am in auto mode, and am unable to trigger on single. Is that possible? I can put it into roll or auto mode, and stop the trace after a key press and then search for the pulses. This I have to zoom in to see the ascii code. Using RS232 trigger and rs232 ascii decoding. my rigol ds1054 will not decode the characters (displays '.') until i zoom in sufficiently on the stopped trace, and then it decodes it - why is that?
So two questions!
Thanks all!