"Incompatible with other applications(s) using the same shared user ID" when installing Google Play service?
What is get my phone from local production? 

Since you mentioned about custom system are you referring to a modded ROM like Cyanogenmod, Paranoid Android etc? 

You have custom recovery in place? If so, grab the latest Google Apps from here appropriately for Android 4.0.4 aka ICS, more than likely, this version of gapps.

Reboot into Recovery, select:


Wipe Cache
Install from zip, select the gapps you downloaded
Then when install is done, reboot.