Would look into this issue.

Developer note:
This is a documented regression since sculpt mask implementation (http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.64/Sculpting#Limitations). Would check whether it's easy to resolve before the release.

I should have read the release notes before posting this, sorry. Thanks for checking this anyway, Sergey.

Well, i've fixed the issue in svn rev50827, so would update release logs :)

Thanks for the report, closing it now.

Unfortunately, something went wrong with this change. Reverted the changes, so 2.64 release would have new feature (which is sculpt masking), with some regressions (which is displaying mask in favor of diffuse color).

We would fix this properly after the release.

Re-opening the report.

Should finally be fixed in svn rev51510 :)