Nikon d90 -self timer using flash?

I have a nikon d90 and i'm having troubles with figuring out my self timer! I know how to set up my self timer and how to make it have multiple frames in a row. But i can't seem to figure out how to do that when the flash is on! Whenever i do ^^ those settings and turn the flash on… It only takes one picture! Please please please help me! I think i'm going mad trying to figure this out.haha

if you don't know what i'm talking about here is a video explaining what i already explained above! I just need to know how to do this when the flash is on…

10 points!

I would guess that this won't work using the internal flash due to the recycle time needed to charge the flash capacitor. It can take a couple seconds for the flash to recycle if it uses maximum power.

This may work with an external flash set at a low power.

Edit: see page 73 in your manual. You will only get one shot per each time the shutter release is depressed.