Garmin 430 user waypoints

Hello,
I am a VFR pilot and I currently have a 96C in which I loaded some 700
user waypoints, neede in Italy to find VFR reporting points and
airstrips. My new club's airplane will have a Garmin GNS430. I contacted
Garmin in order to know if it would be possible to load waypoints
through the serial ports, but they said NO.

Looking in depth in the Pilot's manual and in the Installation Manual,
it looks clear that many EFIS do that:
-Bendix King EFS 40/50
-Collins Pro Line 21
-Honeywell Primus 1000
-Radar Graphics
And it is clear too that they connect through Serial 2 RS232 port. On
the installation, I do find some of the OUTPUT packets but there is no
mention of the INPUT required to load waypoints.

Do anybody know something about this?