champion juicer

It's a family tradition of ours at Christmas to make poppy seed cake - kind of like a sweet bread dough with poppy seed paste spread on it which is then rolled up like a swiss roll and baked.  Mum has always done it in the past, but I'm trying to take it on now.

I need to figure out how to grind the poppy seed though.  Last year I tried making the paste with unground poppy seed, and it just wasn't right.  I have a Champion Juicer, with the grainmill attachment which I use for grinding wheat for my flour, and I was wondering how it might go with Poppy Seed.