passing parameters with nlapiResolveURL when record opening in edit mode

I'm using nlapiResolveURL() to open a record in edit mode. I was previously using this function to make a copy of a record and open it in edit mode. When it was set up that way I was able to pass parameters in the url. Now that I'm just opening the record itself in edit mode and not creating a new record and opening it in edit mode, I cannot pass parameters in the URL. A custom button is triggering a client script that has nlapiResolveURL() opening the purchase order record in edit mode. Is there a way to pass