Error message not displaying correctly when user has not established a 5250 connection

We've created our own program to do additional password validation, but we're running into problems displaying the error message. We used the sample program from the iSeries Security Reference Manual as a template. Messages are sent using the SNDPGMMSG command. The message displays correctly when the user has already established a 5250 session. However, if the user is going through iSeries Access and is prompted (by a pop up window that displays: Password will expire in XX days or password expired) for the user ID/password, the message is not displayed. I suspect it is because the 5250 session is not established. Any thoughts?