crating a new keymap file.

The names of the files are

km-xxxx.ini

where the xxx is replaces ny the hex number of the layout of interest.

The files have 5 section

[noshift], [shift], [altgr], [capslock], [shiftcapslock]

In each section there are multiple lines for each key
An example line looks like

Key10=49:49

In this line, 10 is the X11 scancode, the first 49 is the keysym value,
the second 49 if the unicode value of the key.  This is the definition
for the 'noshift' '1' key on a en-us keyboard.  In this case, the keysym
and the unicode value are the same.  Here is an example where they are
not.
This is the definition for the backspace key.
Key22=65288:8

And this is the star on the keypad
Key63=65450:42

To create a new file run xrdp-genkeymap filename

Example ./xrdp-genkeymap /etc/xrdp/km-0409.ini

Note: You need to have rights to the /etc/xrdp directory.