Would you mind describing what you mean by “I have to recopy it from the HD I have attached”?
The binary, configuration and support files should have been installed under the /opt directory. On a properly uNSLUng device, the root level /opt is a symbolic link pointing to /share/hdd/conf/opt. So, all of the files should already be on the external HD.
Are the files on the drive those which are being altered or is your /opt directory still fully located in flash?