Ginger dwarf-lops

Question
I have three breeding pairs of dwarf-lops.  One pair - mother black/father white and I get blacks, whites and greys.  I understand this (I think).
The other two pairs are mothers ginger/fathers a very pale cream and grey points.  When these pairs have babies they are nearly always white, grey, black but no gingers.  Why?
I bred the original gingers, one was the mother and the other one is from her.  At that time when I had just started, I wasn't that interested in the outcome.  All the rabbits were in together at that time so I don't know how the ginger came about.  Can you help me?

Answer
It is a little hard to answer because I am not sure what colour ginger is compared to the proper terms for accepted colours. Though you might be in Europe, where colour terms are different.

However, the most likely explaination is that whatever ginger is, it is a recessive (weaker) colour. That would mean both parents would have to have at least one gene for it. Obviously  any ginger coloured ones have it, but the mate would also have to be either ginger coloured or be hiding one gene for ginger in order to produce it.

I am guessing ginger might be what we call fawn (or orange, depending on how intense the colour is, but the genetics of the two are the same). If so, it is a very recessive colour. Is it similar to the rabbit pictured here: http://www.bunnyrabbit.com/rabbits/lionheads/linda.jpg ? That is a fawn.