Force building derivative images

Hello
At first this module works great for D6. I've read many "not working" messages but it works. Maybe people should refresh page with F5 to see watermarked image.

Here is my question.

If I check both regenerate derivatives and apply watermark checkboxes, it first applies watermark and regenerates derivatives. So watermark disappears. Is there any way to change that order?

Or...

Is there any way to force regeneration of derivatives before applying watermark?