Flashgun Help

[HebburnMackem]

I've finally got around to playing with my new flashgun, but need help with exposure.

I have the Canon 550D + Speedlite YN565EX, both TTL II

I like to shoot in aperture priority quite a lot, so when I focus on a dark subject, the camera wants to expose for 1 - 3 seconds, which is far longer than needed when I have the flash.

Do I have to go Manual when using a flashgun (to set exposure duration).. Or is there something I'm missing.

Because they are both TTL II / ETTL, I was expecting this not to be an issue.

ta