How do i solder on a data wheel on the 2500?

Is it an easy job? What equipment do i need? Is there a step by step anywhere? I already have a soldering iron (my mums from her workplace), but what else?

I was thinking about buying the part from VST (2500 rotary encoder) and getting the technician at my local music shop to solder it on. I just don't feel comfortable soldering at all :S