How do you post a "want to trade" ad?

[Beemermark]

While it would seem obvious I cannot get the links to work. I've placed ads to sell but I want to post a WTT ad.

 

[Beemermark]

The next step (2 of 3) is to choose a category. Unfortunately the pick menu is blank and I can't get past step 2.

 

[kxl]

I believe you also need to be logged in.