CC-BY-SA and Apple licensing incompatibility

CC-BY-SA and Apple licensing incompatibility

I get a lot of messages from people who want to use or are using my graphics in iOS games, but according to this thread http://opengameart.org/forumtopic/lpc-in-ios-games-sadly-not-possible the CC-BY-SA 3.0 license is incompatible with Apple's licensing requirements (relicensing all assets under the Apple license). Also the anti-drm clause of the CC licenses have to be waived in order to make assets useable in iOS games.

Is there any workaround or do I have to waive both the SA module and the anti-drm clause if I want to allow my graphics to be used in iOS games? I'd actually like to keep my graphics CC-BY-SA, so that derivatives stay libre (especially my space ship construction kit which exists only to spawn derivatives). My main concern is that someone licenses some ships under a different license and someone else (or I) who makes similar ships (what is pretty likely) gets trouble for copying those pieces.