Using variables or RPM macros in RemoteAssetUrl?

Hi all, when building containers, one can use #!RemoteAssetUrl: together with the download_assets service, so OBS downloads the files when uploading a new package version. Very handy, but one thing seems to not work: Can I use variables or RPM macros in the URLs? If so, how? I can use prjconf to set docker build args aka "ARG". Would be great if this worked for the assets, too... Kind Regards Johannes