if banners enabled, how does backend get print job file?

[Ted Tanaka]

I wrote a custom backend, and it receives the print job via stdin just fine when banners are disabled.  But when banners are enabled, the backend gets the first banner page as stdin, and the print job and second banner page are not processed by the backend.

Also, they are stored as 3 separate files in /var/spool/cups, so I know CUPS is correctly processing the job.

Can someone tell me how my backend can access both the banner pages and the file to be printed?  The backend appears to only be called once for the entire print job (2 banner files and user file).

Thanks!