[RCU] Importing contacts from horde:turba

I am sure this must be a common question. How does one imports a set of contacts from a Horde:IMP:turba environment?

I can export the raw data from the source system into a CVS like file. Is it a simple matter to just use perl:DBI to insert the data into the roundcubemail:contacts table? I have looked at that option and noticed that contacts are referenced via user_id. My roundcube instance already has all the roundcubemail:users table populated. Or is there some php code in the source tree which I can leverage to make the job easier. I have about 5000 contacts or else I could do things manually.

Many thanks in advance.

Russell