Volvo 2002 V70, 2.4 Bifuel CNG - Few problems.

[nonlin3]

Greetings, firstly wanted to say hello Just registered.
So, I got a V70 2.4 with factory built-in CNG installation, necam variant.
My main problem is that sometimes (more often nowadays) the engine switches off when running on CNG (on a petrol works just fine), by switching off I mean that it just dies completely. I have to stop the car, switch manually to petrol, turn the ignition off and on just to start it again.

I know that CNG overall is better than LPG but it's not popular in Poland, we got ver few gas station around the country (there is only one in my city), also I can't find a proper workshop to maintain my CNG installation, everyone refuses to touch it because it is factory built-in. So I decided to remove CNG from car and install LPG (station around every corner, cheaper than CNG, every kiddo can fix it etc).

If anybody made that kind of coversion I would like to know basically every detail (or just removing built-in CNG):

I assume, CNG is programmed in the main ECU, is there a possibility to reprogram ECU to make car think he is just an ordinary gasoline vehicle?
I read when you remove CNG components, there are tons of errors stored in the memory and ofc a check engine light on.
Also I would like to have a gasoline lvl indicator in the right place (instead of the CNG pressure/lvl), because at the moment current petrol level is displayed on the left LCD panel.
Like here http://media.clusterrepairsuk.co.uk/...79331_big.jpeg

Sorry for the long post and ... bad english