Resolution:
rtbrand simply looks for a marker in the executable file (an example is rtserver.x) and replaces it with the license key provided by the customer. This marker is just a string that gets replaced by the string passed in. For example,  suppose the marker is: 12345678-12345678-12345678-12345678 and the customer license key is: C0E19067-DDEE417B-C76017E5-C246112D, then the marker in the executable is replaced by the key.

rtbrand replaces rtlm which was used prior to SmartSockets 5.2.