many years ago i was on a mission to develop an rtd client in java. i searched for information and found
a python implementation. at the time, i didn't know python so i never did anything with it. python can read
and write excel files, and i assume it can also read and write openoffice/libreoffice files. depending on your
motivation, you could start with the python client and integrate it with code to interface with libreoffice.
there's no documentation with python code and it would probably not be easy to get it working. the python
rtd client is still available on the web and there's a microsoft paper on how to develop an rtd server. with
both of these you can figure out how rtd works and likely get it working.
https://github.com/brotchie/pyrtd