Installing an IGH in a Trek District SSB

[mikkel]

I own a Trek District SSB, which uses Trek's proprietary belt drive system. I'd wanted a bike with an internal gear hub, but they only offered a 3-speed version as an upgrade, so I decided to buy the SSB and upgrade it myself to something a little beefier.

The SSB has the same frame as the IGH 3, so it already has the cable guides for the hub. I'm going to take my bike to a local community shop to do the conversion, so I should have people on hand to help me with any problems I run into. What I am looking for help with is my shopping list (although warnings and gotchas are welcome).

The IGH 3 claims to use a Shimano Nexus 3-speed hub in the specs, but shows a picture of a Shimano Alfine hub. Would this work, plus this shifter? Will I be able to swap the drivetrain components over from the SSB to the new hub, or do I need to order replacements for anything?

Thanks in advance.