Api call with keys which have a space

Dear Appian Community,

i want to call a pretty common webApi with a regular JSON request.

Usually no issue. CDT/Map tojson() go for it.

Just faced that a key is mandatory at the receiving end which has a "space" in it.
But CDT field names and Map paramters are just working without space.

To show what i mean:
the API expects a JSON parameter like "Creation Date: "
my CDT has "CreationDate" (so space missing) 

Any ideas to solve it?
Still amazed that i never faced that so for.

kind regards,
Richard