ConfigMgr SQL Backup Service on the wrong volume - Workaround

Your going to install a ConfigMgr 2007 with the database stored on a remote SQL Cluster server. During the installation of the database there will be installed a ConfigMgr database backup service on both cluster nodes. This service is named SMS SITE SQL BACKUP. By default during this installation the volume with most free space is used to store the service. This can cause various problems on a cluster. E.g. Systemstate backup fails, as a service running on a shared volume cannot be accessed.
To bypass this behavior there should be created a file named NO_SMS_ON_DRIVE.SMS on the root of each volume of the cluster which shell not be the volume for the service installation.
If the service installation is already done on a shared volume, it's getting difficult.
There are various opinions how this problem could be solved...
For example one is to move the Configmgr database to another server, create the file on the volume and move it back to the server, so that the installation is running once more and the volumes with the file will be skipped. Another option which is discussed is to do a site repair.
Then i've found the following post from Razmus on Microsoft forums. Then i did the following:

Note: X=Wrong drive letter, Servername=Your MgmtPoint

1. I moved the service folder X:\SMS_Servername from the wrong volume to the desired one.
2. In the Management Points registry go to the path HKLM\SOFTWARE\Microsoft\SMS\Components\SMS_SITE_COMPONENT_MANAGER\Multisite Component Servers. Below this key there are listed two subkeys named as both cluster nodes. On each of this key there is a value named Installation Directory. Here should be the driveletter also changed.
3. In the registry of each cluster node go to the path HKLM\SYSTEM\CurrentControlSet\Services\SMS_SITE_SQL_BACKUP_Servername and change the value ImagePath to the new driveletter also
After restarting the service SMS_SITE_SQL_BACKUP_Servername on the cluster node the new execution path should be changed to the new volume. Afterwards i removed the service folder from the wrong volume to make sure that the service is really running on the selected volume. This seems to work. The only problem is still have is, that the folder is still created on the wrong volume when the service is restarted. But it only contains the logfile. I can live with this behaviour, as the executable is running on the correct one.