Create New Job from Sales Order Popup. Manipulate DOM to provide more parameters

Hi Everyone

I have the following scenario:
[LIST]
[*]User creates a Quote (Customer Only)
[*]User converts quote into Sales Order and needs to add a new Job
[*]User clicks on the + icon next to the job field to create a new job in the popup window
[*]The job is pre-populated with the Customer from the Sales Order Entity field
[*]User populates job fields and saves
[*]User saves Sales Order
[/LIST] What I'm looking to achieve is to pre-populate other job fields from the existing sales order field values. 

I figured I could try and attempt to do this by manipulating the onclick value of the + button to pass through more parameters into the URL.  When I inspect the element, the current button's onclick value is: function() {setSelectValue(document.forms['main_form'].elements['entity'],-1); document.forms['main_form'].elements['entity_display'].value=''; document.forms['main_form'].elements['entity_display'].isvalid=true; NS.form.setValid(true); Syncentity(true);return false;}