debug or reproduce the creation of IDOC

Hi All

Purchase Orders (in our MM Module) are being transfered via ALE IDOC to the Vendor in our company. One IDOC has some strangesegments currently . I would like see how is this Idoc made up or created.

Is there any way I can debug or reproduce the creation of this IDOC generally. Right now it is just a kind of black box for me.

However Ireally need some hints on how to achieve that.

Regards

Marco