Can I use MIUI's auto SMS + MMS backup + restore thing on another custom ICS rom? MIUI's built in SMS + MMS backup works quite well. However, I want to try out new custom ROMs. Is it possible to add integration of that MIUI service onto another ICS rom?
Answer: No you can't.

Reason: You can't install the MIUI Backup App on another rom, because it's a signed system APK.

Solution: Use a backup solution which is available for all roms. If you just want to backup and restore SMS, then use the free https://play.google.com/store/apps/details?id=com.riteshsahu.SMSBackupRestore

Source: I'm a MIUI Beta tester and former moderator on the original forum en.miui.com