Hi Danilo,
It depends on whether you are storing the content of the file or the file it self.
If you are storing the xml content only, i would go with what Maik Delly has suggested.
But if you need to store the file it self, I would recommend you to keep your own table so you can set your own data type either varbinary or image or xml with a RecordID for each file.
You will then store this RecordID in related SBO table UDF.
Regards
Edy