It is said that in N=2 supergravity coupled to vector multiplets and hypermultiplets, one can gauge the R-symmetry by equivalently gauging the isometries of the corresponding hyperkahler cone over the quaternionic Kahler target manifold of the hypermultiplets (see e.g. 2nd paragraph of http://arxiv.org/pdf/hep-th/0104215.pdf).
I would like to be able to see explicitly why gauging these isometries is equivalent to gauging the R symmetry. I cannot find this explained in any papers/books (at least not at a level that I can understand it!)
Can anybody offer an explanation?