Custom product due dates in order creation

[davoram]

I want to add my existing clients to whmcs but I cannot change the hostings billing cycles start and due dates to adjust to the ones my clients have.

 

I tried to achieve this by generating orders without invoices, then I change the orders product due dates but then I cannot generate an invoice for the order it just do not show the "generate invoice" option when you edit an order, as when the order was originally created.

 

How can I achieve this ?

 

Thanks for your suggestions.

[davoram]

Ok I will ask for two specific cases.

 

Considerations:

 

Invoice created Email: set to 30 days before due date

 

Invoice Reminder Email: set to 15 before due dates

 

 

CASE A ( it is clear for me)

 

 

Client which hosting plan finishes on the 30 of December 2009 (today is july 4, 2009) I understand I have to enter his product info on an order and do no generate invoice, whmcs will created 30 days before due date.

 

 

CASE B ( This is not clear for me)

 

Client which due date is July 15 2009 (today is july 4, 2009) I do not understand what to do cause if I generate an invoice in order creation the due date will be wrong, and if I do not generate it WHEN will the system will send the creation invoice email and the reminder invoice email it there is less than 15 days?

 

 

Thanks!