I can supply the exterior wiring for you, i'm a bit confused about why you need the park/neg pin out?
Is this an automatic or manual transmission?
Here is the radio circuit, which may or may not be involved, check it out, and i'll see if there is another input you can use,,,,,,i never heard of the park brake thing,,,
If you want the park brake circuit,,i'll sure send it to ya,,,,i just cant quite figure it into the DVD palyer :-)
Let me know
Thanks for asking!