FAO Dylan,
I have recently tried using Ajowan seeds in 2 different recipes for base sauce and do not think that they are "the missing taste". They are a very strongly flavoured aromatic seed which are very readily available in my locall area from asian grocers.
I hope this is of some help but sadly I don't think it's the answer you were hoping for, in fact I would go so far as to say the flavour detracted from some promising results that I have recently been achieving,
cheers anyway
Blondie