Yes, it should be possible with your current version, but would require a bit of work.
You would have to add your own water 'airport' with your own water 'runway' in AIRAC's (FSXPilot home directory AIRAC folder) apt.txt and rwy.txt. You would need GPS coordinates for that 'airport' and 'runway' as well as elevation and 'runway heading and a name for the airport and runway.
There are also some water airports in FSX. You should be able to land on these too. Please google this ...
If you want to suppress setting of gear before a water landing -> enter "set nogear" in the text command box.