How to get an indeterminate progress indicator to work?

Hi.
I'm having trouble getting an indeterminate progress indicator to work. I do:

[progress setIndeterminate: YES];
[progress startAnimation: self];

 ... some work here which does make the run loop spin, so
     timers do get fired normally ...

[progress stopAnimation: self];

Somehow, however, I don't see any change on the progress indicator (even its
looks don't change, even if I set it to be indeterminate in Gorm).
Can anybody help me with this?

Regards
 Saso