Ok, this adapter will save you having to cut/run extra wires -
http://caraudiosecurity.com/shop/product/products_id/8115.htmlBut it can be made to work with the adapter you have.
You will need to run an ignition switched 12v live from a spare point on the fuse box across to the back of the head unit.
Once you have run the wire (which I would add an extra fuse near the fuse box end) it will need to be connected to the switched live input on the back of the headunit (probably the yellow wire). The 12v permanent live on the loom/adapter should then go to the red live wire on the headunit.
Not sure what part of the country your located in? If you local I would be happy to help