Frank,

there could be alot of things going on and without seeing the site I can only guess. The top menu (container) is a table. You can center the table in whatever it is in. Maybe you want to center the items themselves, then you should be able to center them text-align:center.

My favorite way to approach a problem like this is analyzing it with the help of the web deveoper extension in firefox. You can download it from the Extensions menu item.

Peter

I know I had similar problems. 

I believe there are classes that are probably effecting the position of the menu.  I was wanting to apply certain padding to each menu item, and when I used the SolPart menualignment="Center" attribute, it seemed to try to justify the menu and screwed up my spacing. 

A work around that worked for me was to edit my skin, dropping another table inside your current MENU td, center align this table (and you can give it 0 padding, border etc) and then drop the MENU into this (so it's one nested table down from where it was).  You can then leave the alignment 'left' on teh MENU as it's your new nested table which has the 'center' applied to it.

Hope this helps,

R.