Your EP45-UD3R is one of the most compatible boards.

10.5.7 works now native on ICH10 (P45/X58...), I only neeed the LegacyIOAHCIBlockStorage.kext to avoid the orange drive icons.
Also had to switch back to 10.5.6 sound, for the time being.

My test iPC partition works well, as same as my main retail 10.5.6+10.5.7 delta EFI partition setup.