Question about particle speed

Hello. I've been trying to make a particle effect that simply should not move from the prim's center. But if I set PSYS_SRC_BURST_SPEED_MIN and PSYS_SRC_BURST_SPEED_MAX to 0.0, no particles are generated. What is the correct way to generate particles at 0 speed?

EDIT: By the way. I'm using PSYS_SRC_PATTERN_EXPLODE as my effect.

EDIT2: Meh, never mind, setting it to 0.009 made a rather convincing effect.

EDIT3: Seems anything under 0.004 shuts particles off. So for the record, 0.004.

If you want the particles to appear at the prim's centre then why not use PSYS_SRC_PATTERN_DROP? EXPLODE does as it says on the tin and shouldn't expect to see a zero burst speed.