Ok I went to Edit->Edit Preferences->Sorting/Grouping and I chose enable custom sort values for individual artists, composers and albums and it just magically sorted the way I wanted it to. Sort By still only shows Name and Count.
Thats right - the thumbnail browser only sorts by name or by album/ track count. If you display Sort Album Artist, then of course sorting by Name will in effect sort by Sort Album Artist
To resurrect this topic from the dead...
This is not what I am seeing. On the thumbnail browser (the column on the left) on one machine, it is sorted by Sort Album Artist, but Album Artist is displayed. So, for example, Bryan Adams shows up under A (since the Sort Album Artist tag is Adams, Bryan), but it displays on the list as Album Artist, so I am seeing "Bryan Adams" under A, which is exactly what I want. On the left column, I have Album Artist selected, but it's sorting by Sort Album Artist.
The issue I have now is that I just installed MusicBee on another computer and duplicated the settings that I have, and I cannot duplicate what the other computer is showing. The thumbnail view will not display the Album Artist and sort by Sort Album Artist.