help chemistry

Where can I obtain Zinc-related parameters? I use HyperChem, which has until Amber 96.

I have been asked to model a mutation in a protein which has Zinc fingers. It is a phosphorilation, so the charge of the Zn ion is important and to maintain the finger structure I need to establish that it is coordinated by 4 cysteines. Unfortunately Zn iones are not recognized.

Please, if anybody can give me some guidelines, I would be very grateful.

Best regards,
Carola Bruna Jofré
Universidad de Concepción