@bjarneo:
Ok. For pump control, the 'third' terminal output (next to the temperature probe inputs) is used, not the relay outputs. This is also just a control signal, so you need something to 'amplify' the signal or 'drive' the pump. The 8A LED dimmers are great for this and very cheap. Have a look at the documentation. You can use a switching PSU to power the dimmer and pump.
If the relays are removed and bridged, you'll have a 12V control signal on the output terminals. It can't supply very much current though. SSR's are designed to accept a pretty wide range voltage on the input (control), 3-32V in your case. Internally it probably uses a zener diode and resistors to limit voltage and current to the input optocoupler, so you don't need to anything else than make sure the input signal is in the specified range.
Finally, you probably can't use the SSR to drive the pump at all, as a 'normal' SSR can only switch AC.
As a gentle reminder, working with mains can be dangerous. Electronics is fun and it's good that you want to learn, but asking questions on forums only gets you 'so far'. If you're not confident in doing this yourself, I'd recommend asking local forums, friends, relatives and such for someone with a bit more experience for some 'hands on' assistance.
