I think these connectors are called BMA (blind mate adapter), OSP/OSM or RPC (Rosenberger Precision Connector), depending on the manufacturer. However there are several different Rosenberger series, I once was told it's RPC-SP and 10S732-K00N5 could work as RPC-SMA Adapter. Though this one is not affordable and not available in single pieces.
The original adapters are Lecroy LPA-SMA, LPA-K (3.5mm) or LPA-BNC.
You should find some compatible BMA/SMA adapters on ebay. However they don't lock in, so you'll need some external mounting plate and screws to hold them in place.