Why would I use Project Insight to create invoices if I already do so with my accounting system?
The invoicing system was designed to allow the project manager oversight as to what items on a project have and have not been invoiced to the customer. Some time and expense items may be billed simply based on the date of occurrence, while others may be billed based on deliverables. With Project Insight invoicing, you can identify all invoiced items to help communicate with the customer as to what has and has not been billed to their accounting department. You can roll up line item entry details into more general invoice line items, while maintaining access to the detail if you need to further explain, audit or justify the items charged on any invoice.
Invoicing was not designed to track payable invoices. Payables are normally entered manually as fixed expenses against a company, project or task. If you want to reference the actual invoice, you could place the reference information in the expense entry description.
Help references for using invoicing: