Menu Items lose their Itemid's

After SEF Advance activation (Joomla 1.7), all menu items lose their Itemid's. The module assignement is no longer possible....
Is that a known issue?
please help!

It's Itemid issue: www.sakic.net/support/faq/sef_advance/#19
Send the admin password and FTP and I will take a look on your site.

Because of security reasons, I can't give you full access to the website.
All items are connected with menu's and have an Itemid...

I can't say anything if I can't have a look on your site. All I can say generally is already explained in that FAQ. It is some specific issue related to your menu structure.

No one has this problem?! That can't be.
I have added a new testmenu, added a menu item and linked to an categorized article...itemid is there with and without sef.
As soon as sef advance is activated....itemid is gone!!!!!

I already linked to the FAQ explaining why it may happen. I can't GUESS what happens on your site. Without looking at it I can't possibly know what is wrong. It is related to how you built your menu. Provide the access and I will find what's wrong. If you can't you won't get one, simple.