sergyh,
If you are publishing the form on a machine with an OS different than the PSW machine(ex. publishing from XP to a 2003 server), it will not work and will not preserve the custom page size settings. This is a known issue, and I believe it's somewhere in the release notes.
There might be a workaround that worked for me, however. Before publishing to PSW, go to File->Print. There, check and uncheck any options just to enable the button "Save Print Options". Once enabled, click it. Then, publish your form to PSW, and see if it keeps the settings. This has worked for me.
Hope that helps!
Regards,
Raphaël Lalonde Lefebvre