Nobody calls BD East Pakistan in Pakistan.
You people call it east pakistan or not may be a metter of debate. But matter of fact is that Indian bengal is still called as "West" bengal which effectively makes bangladesh as "East" bengal. Even after so much demands, GOI has refused to rename WB as simply bengal.
Similarly, supreme court of India thrashed a petition which seeks to remove the reference of "Sindh" from the national anthem as it belongs to pakistan. So effectively Sindh is still in India as per the national anthem. And GOI and judiciary refuse to ammend it.
Something to ponder upon.