Sergey,
I believe you can only create custom sizes for DMP's under 9X. At least I can't find a way?
>You can create report with custom paper size under Windows 9x. For WinNT and Win2K see mskb #
Q304639 HOWTO: Find Paper Size for Custom Print Sizes Under Windows NT and Windows 2000 and mskb #
Q157172 How to Create Custom Forms in Windows NT 4.0 and Windows 2000.