Need advice on how to properly ground an HU - 2006 Suzuki Jimny

[Rijndael]

I recently had a new sound system in my jimny (total overhaul, replaced HU, seps, added amp and sub) installed. Di ko napansin agad but i realized i was getting alternator whine in my speakers. I did some research about it and isolated the source of the noise to the HU.

After taking the HU apart i found that the installer had used the ground used by the stock HU, which based on reading forums is not a good idea. I was hoping someone could teach me pointers on how i can ground the thing properly or point me in the direction of a decent shop who can?

[OTEP]

Go to jemson. He does jimny work for me. His thread is in the security forum. Thanks.