It's so obvious that surely anybody could work it out for themselves... just enter the sequence of waypoints. Of course you'll have to manage the altitudes yourself, and you won't get LPV or LNAV - just like a Mk I GPS approach.
The GPS approach to my own home airport (KPAO) always has to be manipulated along these lines, because ATC never, ever, ever uses the official IAFs. So you have to select one of them, then manually to "direct" to the IF they use. (If you care to look it up, the official IAFs are SAPID and LICKE, but you are almost always given directions to DOCAL, very occasionally vectored onto the ABSIW-PUDBY segment - even when my flight has taken me right through SAPID I've still been given "direct DOCAL").