Even since I bougth my IS I had the recirculation damper arm broken. It is easy to see through the glove box, where the cabin filter is located: if you switch from outside to recirculation mode, the cabin filter is visible. Switch again and the access to the filter will be blocked by the damper. Mine was freely moving up and down but using these instrustions from My.IS I repaired it today.
http://my.is/forums/f127/is250-air-r...-servo-414274/
I used 6/32 2inch screw with lock washers and and no glue

If you want to repair it with the original part ( see it here)
http://is.sewellparts.com/oem-catalo...S350-2007.html , the part that you need is part #87020A. To do that though, I am pretty sure you have to completely remove the blower assembly which can be a lot more work.

Alltogether it took me about an hour and a half.