Request for help: diagramming a relay

[BailOut]

In order to work around the issues I'm having with my Pioneer AVH-P3100DVD head unit always prompting the OK screen when the unit is restarted while viewing a DIVX file, and often failing to restart the audio at that time, I am pondering using a relay to keep it powered as long as the 12V accessory bus is powered up but having it draw power directly from the battery rather than the accessory bus.

I think I can do this with a standard 5-pin SPDT automotive relay but would like confirmation. I would wire it as such:

30: fusable link to radio's ACC line
85: ground
86: fusable link to 12V battery
87: not used
87a: fusable link to 12V accessory bus

Would that work?

And would it be enough, or would I need to yank the "ACC Cut Relay" as well?