Our sinodefense web site states the JH-7/A is in service with PLANAF 6th division, and JH-7A is in service with PLANAF 28th division.
I checked with china-military.org's and it reports the following:
16th Regiment at Shanghai Dachang - JH-7
17th Regiment at Yiwu - JH-7
27th Regiment at Ledong - JH-7A
These guys made 4 updates in 11/2005, so I think the data is relatively recent: