Replacing Jobo ATL-1000 circulating pump

I'm about to replace the circulating pump in my ATL-1000. The pump is a Comet Elegant 12V. I don't know much about electronics and I'm unsure about the polarity of the wires. The old pump has two white wires, one with a black line. The new pump has a brown and a blue wire. What is + and - on the two pumps?

Trond

Just for future reference. The polarity does not matter according to K.-D. Seynsche Fotolaborservice (Dead Link Removed).

Very friendly service and he has parts for Jobo processors.

Trond