Hi,
Approach a local engineering company, it is not a hard job at all(engineering wise), they will most likely either just redrill 5 holes in pcd that you want, or weld your 4 holes, skim flat then redrill to 5 holes and tap, make sure you can get the offset you need before going ahead, I'm sure you can, but wouldn't want you to go ahead and find you couldn't.
Please pm me if you are in position for a sale please, thanks, would do these in gloss black for my mercury grey sapphy!!
tabetha