Just finished some of the same work on my Waterstage with RVS56.183 controller. The BSB is a Boilers System Bus for control between heating en thermostat etc. There is also a LPB bus (Local Process Bus) for connecting other apparatus for controlling the RVS.
In my case i bought a OZW672.01 webserver (in Greece!) to parameterize the heatingcontroller. There is a nice webinterface, but for controlling by means of external programs, you have to implement your own program and use the ajax.asp from the webserver.
see also http://www.ip-symcon.de/forum/f52/php-x ... gen-16098/
I have done (not quite finished) my programming in ASP.
48m2 Heatpipes, 2200l buffer, Resol Deltasol BX, DL2, vBus/lan, Chint 3CPL2.8KTL, 16*Csun 190 kWp, Waterstage WSHA155DA, AOH54LJBYL, RVS41.813/327, OZW672.01