Hi A D,
I think it is not right way to do but I finally generate outbound reservation IDoc.
I found the Enhancement 'MBCF0007' which runs AFTER saving the document,
If you can try to write easy ABAP in 'EXIT_SAPMM07R_001', you will create MRESCR IDoc by using function module 'ALE_RESERVATION_CREATE'.
If you found the better way, pls let me know.
Thanks!
Regards,
Kenji