Dynamic number of subreports

Hi.

I'm starting with jasperreports and I'm asking for help for a report (truly, an invoice) design.

I'm not looking for a final solution (I have to do my stuff, just an example, schema or design for a *report* like this:

•  The report is a mobile phone invoice.
•  There is a main customer data with some mobile phones.
•  Invoice has these pages
  • Customer personal data and summary (it could have more than one page).
  • Force page break
  • Mobile #1 summary
  • Mobile #1 detail  (it could have more than one page).
  • Force page break
  • ...(as many times as customer mobile phones)...
  • Force page break
  • Mobile #n summary
  • Mobile #n detail (it could have more than one page).

I have the first part (customer personal data and summary). My problem is now, when generating dynamic data with different msisdn numbers:
Well, my questions are:

 1. Does this design go in one .jrxml or two (customer summary and mobile summary/detail)?
 2. How can I invoke and generate all the mobile pages for each customer, when every customer could have different mobile amount?

Any help would be very appreciated