Does not work with the default kernel. The driver for this has become part of the standard kernel from 2.6.17RC1, but was included in Xubuntu's 2.6.15 kernel. Not included in SuSE's 2.6.16 kernel, unfortunately.
I compiled the 188.8.131.52 kernel and installed it onto my Muramasa. The sdhci module is not loaded out of the box. Manually `modprobe sdhci' and `modprobe mmc_block' as root. Then the SD card is automounted. I think I will add those two modules to the MODULES_LOADED_ON_BOOT list via YaST2 -- System -- /etc/sysconfig editor -- System -- Kernel.