G'day Ricko, welcome to GPSPower. I see you asked about HEMA OziExplorer maps elsewhere which would probably be the ultimate solution for you if possible.

Dunno about anything else [like primo etc as far as topo maps are concerned], but you can probably use a Garmin topo successfully on GarminXT for wince. Most of those Chinese generics run WinCE 5 or 6:
[Only registered and activated users can see links. ]
[Only registered and activated users can see links. ]

You can only use images up to 2GiB though, so the full Garmin Topo V5 img is too big but the Lite version is well under 2GiB. There's other 3rd party listings in the index too: [Only registered and activated users can see links. ] [post #2].

The XT software's pretty old now but kinda bulletproof too. Let's know how it goes if you try it.