[Wine] Unable to use Photoshop CS scratch disk on tmpfs

[wildbug]

I am running Photoshop CS under Wine (was 1.1.44, is now 1.3.0) and am unable to use a tmpfs mount as a scratch drive.  Using winecfg I have mapped /tmp (the tmpfs mount) to a drive letter.  It shows up in some dialogs such as Open or Save but not under the scratch drive setting in Preferences.  When it is listed in, say, the Open dialog, the icon is different than the other drive letters (such as C: or Z:), even though I have explicitly marked it as a "local hard disk" in the advanced section of winecfg.

The closest bug I can find is #10461 (http://bugs.winehq.org/show_bug.cgi?id=10461).

Has anyone else gotten this to work or is there a trick or workaround to get Photoshop to use tmpfs space as scratch?  My scratch is on a fast drive now, but tmpfs would really speed up my workflow.