OK, I am developing a D6 multilingual site and am having problems getting my Primary links to display in Nicemenus. A little detail:

I have a seperate menu for each of my (currently) 2 languages, each with a few menu items.
I have made primary_links_source a multilingual variable and set the source to the appropriate menu in each language.
I have set my nicemenu block to use primary links as its source.
I have unchecked Primary links from my Zen development theme

If I show the Primary links menu block directly (not through nicemenu) it works fine and switches as expected when languages are switched. But if I show the Primary links through the nicemenu block then nothing is shown. The problem only appears to be when the source is set to primary links because the nicemenu block will display any other menu without a problem.

Perhaps nicemenu is uncompatible with language dependant primary links? Perhaps I am missing something? Ideas...?