User Defined Waypoints in Flight Plan (*.pln)

I know you can enter user defined lat/long coordinates, but when I load a flight plan from file (*.pln) with user defined coordinates in it, I get an error. I am mountain flying an often need additional points for climb out, terrain avoidance or valley flying. After creating a plan in Little NavMap (2.5.16) and exporting it as a *pln file, I can not read it into Navigraph Charts (file format error, or it just does nothing.) I created a plan without user defined waypoints and it works just fine. Should I be able to load a *.pln with user defined points, and if so is there something I need to do (process or format) to get it to work?
I am not complaining, just asking.

Hi…,

Welcome.

I wonder if the format might not be right. Please see Geographic coordinate in navigraph charts.

Cheers
Ian