How to create new namespace

Hi,
I want to translate the Country Page of Luxembourg into the luxembourgish language, but this name space does not yet exist. I´ve read, the namespaces are created by a parser function of MediWiki. I don´t really understand that.
Can onyone explain to me, how I can create this new namespace LB:Luxembourgish, so that it appears on my “missing languages” bar?

Thx in advance
Nils

Do you know http://wiki.openstreetmap.org/wiki/System_Administrators ?

According to these info you may aks Grant Slater (User:Firefishy) directly when no more feedback is coming here …