You can do it in 2 ways
1.create EDI doctypes/shemas via ISAdminConsole WmEDI link and there is optiont to Install TN Document types and once you install it check in the WmEDIForTN package EDIFFSchema folder it will have the schemas created.
2.Using the SEFParse service located in the WmEDI core package.
For more information review the webMethodsEDIModule userguide on these options.
HTH,
RMG
#Integration-Server-and-ESB#edi#webMethods