flash Sigma EF 430 ST for Minolta- does not fire with camera
 

I have the following problem: I want to use it with the
Minolta Dynax 7000i (as far as I know this flash works with i-series),
but
it doesn't work.
It seems that everything is OK - the flash loads, it fires in test
mode, the camera recognizes it, the infrared is working etc...however,
when I take a picture and fire
camera trigger, the flssh does not fire. It just does nothing. Any
idea
what is the problem?

I would be grateful for help.

Martin