S1000D Brex space is replaced by "_"

In BREX file I defined some values for attributes.Some of these values are two words, for instance, skillLevel value for sk51 is "Bike Rider". In data module when I choose sk51 it shows Bike_Rider and it adds an underline between each space in attribute values. I even tried to add space using special characters (like Control+space) but this time it adds some strange characters instead of the space. 

I would appreciate it if you could help me to omit these underlines. Is there any option which replace spaces with _ ?

Thanks,

Sanam