TextEDParam compile error in CONNECT works in SS3

I have a function in SS3 that accepts a pointer to a TextEDParam structure.

In CONNECT, I added the include file

#include <DgnPlatform\TextParam.h>

This include file looks like it defines TextEDParam. (in SS3 it was defined in mdl.h)

Yet for this function:

Public nativeCode void fplcom_justTxtToEditField(TextEDParam *edParam);

I am getting this compiler error: error C2065: 'TextEDParam': undeclared identifier

Any idea what is going wrong here?