LFTP: Mirror to remote except particular file present on remote

I usually edit my website locally and push it with this command: lftp -u user,password host -e "mirror -c -e -R -x ^\.git/$ my /my; exit" But now, my website dynamically appends data to the /my/data file. I don't have this /my/data file locally. **QUESTION:** How to push without deleting /my/data and its content? Notes: - I could download /my/data and then run the command above, but data added in the few seconds before the download and the upload would get lost. - For the other files/folders, local deletion should be mirrored by a remote deletion. - I don't want to use --only-newer-like operations because clocks might not be adjusted.