Need help creating custom invoices

I am using Zoho CRM for my ad sales, but it does not allow me to create a sales order that will work as an insertion order because I need special fields for each entry, like start and end dates. It seems like I should either be able to create a form in Creator and embed it in CRM sales oder or create a custom form with an html view like an invoice. From all Iv'e read this is doable, but I can't figure out how to use creator enough to do it.

can someone either give me some tips or point me to a tutorial. I have read the tutorial at zoho.com about how to make a custom invoice in html view, but the directions on how to use deluge to customize the invoice template and pull the fields from the form I created just aren't clear enough for me to implement.

Thanks for any help...