When updating EXIF data in a RAW Canon CR2 file the link to XMP sidecar is lost

[apomar]

I am using DowoaderPro from Breeze Systems to download raw data from a Canon EOS camera.
This sw allows to apply IPTC metadata when downloading and save them in a XMP sidecar file.
The downloaded file and XMP are properly read in Adobe Bridge that report the IPTC metadata saved in the XMP sidecar file.
Now I need to use ExifTool to update the raw files with correct lens parameters for a third party fisheye that doesn't set properly the EXIF.
When I run the ExifTool command the lens parameter are properly updated in the raw CR2 file but the XMP file previously associated is no more read by Bridge and all the IPTC metadata set by DowoaderPro are lost.
It seems that setting EXIF tags in the raw file brake the link with the XMP file.
I am setting the following EXIF tags:
-FNumber
-ApertureValue
-FocalLength
-LensMake
-LensModel
-LensInfo

Any suggestion how to avoid the problem?

Thanks
Marco

[apomar]

Solved.
It is only an issue of file time stamp of XMP file vs RAW file.
If XMP file time stamp is earlier then the RAW file (as happens if you modify RAW with ExifTool after XMP has been created) Adobe Bridge do not use the XMP file.
Setting the -P tag in ExifTool command to keep the time stamp solve the issue.

Marco