Won't help much but I bought a 1.8 TS last week that had completely non-working controls. On taking the radio it became clear out the previous owner had unplugged them from the radio - plugged back in and the volume went down to 0, none of the buttons worked.
I undid the bolts holding the airbag module on the wheel, gently moved it aside (still connected, battery off for half an hour first just in case!), then prised the button units off the wheel, disconnected the ribbon cables and threaded them under the plastic ring (that needs pulling away a bit to give enough room). The ribbon cables were badly deteriorated on the first 90 degree corner they go round, so I swapped the units for those from my previous 156. Put it all back together and everything's working again.
There are a number of second hand steering wheels on ebay at the moment, as low as £18.99 delivered, you could swap the controls off one of those and it'd probably sort you out. No need to swap the entire wheel.