We need a more robust invoicing system for Zoho CRM than what is built in. We looked into Zoho Invoice, but its integration with Zoho CRM is poor. I don't want to use more than one application if I don't need to. Therefore, I'd like to continue to have invoices available in Zoho CRM, but with more features. Basically, I'd like most of what Zoho Invoice has to offer, but within CRM.