RSEINB00 flat file to idoc uploading in XI

Hi,

I've searched a lot of posts here in SDN on how to use RSEINB00 to upload flat file idocs, and i tend to get lost as there are conflicting answers...

can anyone give me a clear/consolidated answer on how to use RSEINB00 in XI?

correct me if i'm wrong but the process is basically to upload a flat file idoc (residing in the XI application server) using RSEINB00, then after successful upload you're supposed to see your idoc in SXMB_MONI (the idoc flat file will be converted to idoc xml using the meta data loaded automatically in IDX2 and be passed to the xi pipeline)

is it needed to finish first all the setup in Integration Builder to enable the automatic loading of the metadata in IDX2?

Also what is the difference between executing RSEINB00 in a 4.5B to 4.5B system, and a 4.5B to XI system? (because rseinb00 is existing even before xi). is it the idoc xml convertion? if it is then definitely the importing of the idoc type in XI Integration Builder Design is necessary right?

Hope someone can explain clearly

I'll be more than willing to give points to the answer that will completely explain the concept..

Thanks in advance