Canon 20D with flash

I just got a canon 20D (just for fun, it was cheap). and when I'm using the flash I notice my shutter speed stays the same as when I'm not using the flash, is this normal? on my Sony when it detect I'm using a flash, it increases the shutter speed.

I'm asking this because I'm sitting on 1/15 and without IS it's hard to shoot, poping up the flash still leave me at 1/15... on my sony it would increase the shutter to about 1/60 at least.

I'm on aperture mode BTW.