Pause and play particle animation [in 2.49]

how would I pause (or freeze) an animating particle system for roughly 30 frames (while i pan with the camera) and then resume again?

I’ve tried using the Time IPO in the curve editor but it’s just not working, I’ve tried baking and not baking and so far everything else i’ve googled is for a different blender version so could someone help please?

thanks!