If I were you I'd get hold of the software and cable to talk to the LPG ECU and a willing volunteer to sit in the passenger seat and try to map it a little better - assuming the supplier can't resolve the issues. I wouldn't be surprised if that's all it needs.
Kevin
I've offered the software!  Don't want any payment for it!  You can get the leads and interface off ebay or if you can find someone on the forum with an interface that fits any of these systems...
AC STAG 100 
AG  RAZMUS, SIROCCO 
BIGAS  SGIS N, ELC '92, ELC PEGASO 
D.T. GAS DATEC BASIC, DATEC SUPER, GAS-TECH 
EMMEGAS ICS-03, 
ELPIGAZ VOILA PLUS, STELLA/ELIZA, MILENIUM, NICOLAUS, LEONARDO 
KME BINGO, DIEGO 
PROTEC DIGITAL ORION 
ROMANO RIS 
OMVL DREAM XXI N 
...you'll be able to connect it with the software - the adapter is the same for all of them.
I'd offer you mine but I'm in Scotland.   
