Lightroom :: Upload All Images Together With XMP Files?

We are getting loads of RAW files together with xmp files from our photographers and then do a central post production on them. Our photographers are requested to add certain information into the metadata fields by using lightroom.So they add (by using a template or by doing it manually) certain information for each image - e.g. ratings.
 
Then they upload all the images together with the xmp files - we do get 2 files per image.If we download e.g. an raw image together with that xmp file and store on our disk and then start LR4.4 to do some further work, the metadata fields are not set. (if we use however a text editor) to look into the xmp file then the requested information is there.

If we now simply download the provided xmp again, LR detects a change in the metadata fields and reminds us on that. By clicking on "read metadata from file", we can then see the correct metadata information.So it looks by just downloading a pair of files (raw and xmp) and then import into lightroom , the xmp file is either NOT read at all or only partly. (i believe the first)
 
Any way to force LR to read in and apply the metadata from an existing xmp on import ?

some more information:

- LR5 Beta behaves the same way

- some photographers add owner/copyright information into the camera (e.g. by using eosutility in the canon case) - this is stored in the raw (cr2 for canon) file and lightroom does show this information correctly
 
- i only need to open the xmp file in an editor and save - then LR detects changed/updated metadata information and displays the little arrow which then allows to read/import the metadata information from the file - and then all is fine and the information from the xml file is shown in LR.
 
Here is the workflow:

- photographer imports images into their local lightroom and do some modifications - mainly add metadata information

- photographers provide the cr2(nef) files together with the xmp files to us (upload)

- we download and import the files into LR and rework them and finally export to jpeg including metadata - !!! if LR does not correctly use the provided metadata information from the xml file during import then we end up with jpegs including incorrect/missing metadata

- we publish the jpegs to sell them and the websoftware does provide certain features or not, depending on the metadata (which is wrong in these cases)

- we only recognize the problen then and have a lot of work to recreate correct jpegs with correct metadata files