I tried install Pioneer control app. However, I could not find it in appsotre for my ipad.
Finally, I change the searching method by iphone then found and installed.
The Pioneer control running on ipad (mine is ipad3) very good wor.
It solved the problem you mentioned.
However, I still felt smooth if playing music from music server via Denon .
One more interesting thing:
Use Denon, n70a screen showed DMR.
Use Pioneer, n70a showed Music Server.