I've been able to successfully install Steam in POL after following a hint somewhere else to use Wine 1.7.8. I can log in, download and play Pinball FX2 (from Zen Studios).
Everything seems to work fine except that the game doesn't recognize my Logitech gamepad F310.
I am running on Gentoo, and the necessary kernel modules joydev and xpad are loaded successfully (according to dmesg /dev/input/input5 is assigned to xpad). Wine also sees the gamepad: when running "wine control joy.cpl" there are two devices listed and when testing the gamepad all elements seem to work.
However, within Pinball FX2 the gamepad is ignored.