Just curious if you found a solution to this problem yet?
I too have HK E Channel but not the China E-Channel which bothers me cause the customs efficiency in Shenzhen was slow as heck. (Train station, Lok Ma Chau)
I crossed into Shenzhen 3 times in 4 days , and the stamps are such a waste of space.
Plus they don't like stamping on top of the HK customs stamps so they skip a few pages on purpose........