How to page an API request

[João_Rosa]

Anyone knows how to add pagination to an package request? I have to many e-mail boxes, and I want to get it paged. The xml is simple like it:

<packet version="1.6.3.0">
<mail>
<get_info>
   <filter>
      <site-id>12</site-id>
   </filter>
   <mailbox/>
</get_info>
</mail>
</packet>

Do you know any way to do it? Reference: http://download1.parallels.com/Plesk/Doc/en-US/online/plesk-api-rpc/

Regards, João Rosa