AR sales invoice -- how to set up the accounts?

["Jussi Kirjavainen" <..hidden..>]

Hi!

I'm having problems with AR sales invoice. I can't get any account to show in Record in -dropdown menu. I have tried all kinds of combinations, even totally senseless ones, but nothing shows up. 

In AR transactions I can get my sales account to show as it should in Account, before Description field. Account is set up as type Income, with Income in "include in dropdown menus" Receivables selected. But it doesn't work with sales invoice for some reason.

Am I missing something obvious? Is this explained somewhere in manual? I'd like to start using the AR module, so far I've managed with GL only... BTW I'm still using v.1.2.7

Thanks for help!