Hi Rikard I have similar problem, probably easy to fix.

I customized sidebar menu for a single portfolio item when displayed. (Film directing, Graphic design,etc…- If I choose a portfolio item which has a sidebar menu of course)
The problem comes when I choose the sidebar item in portfolio view – for example Graphic design.
Then sidebar changes from customized (Film directing, Graphic design,etc..) to: (Pages Categories Archive) and I don’t want that. I want to see the same customized sidebar also in Archive for: category in Portfolio items.

I managed to do that in my blog posts, where I had the same problem. Unfortunately I forgot what I actually did.

Thank in advance for your kind answer