Royal Wiltshire Yeomanry

[loupie1961]

I've recently bought a 1944 date RAC beret badged to the RWY. The badge has got a red cloth backing. On wikipedia http://en.wikipedia.org/wiki/Royal_Wiltshire_Yeomanry
I've found that "The cap badge of the RWY is the Prince of Wales's feathers is a slightly different design to other regiments wearing the same symbol, such as the Royal Regiment of Wales. It is worn on the brown beret with a red baize and a black baize backing." First, I guess that being an armoured regiment, the RWY wore and wears a BLACK beret, but I'd like to know the meaning of the red backing... any hints?