How to add POI not replace previous

[bmkrein]

Hi

I am using Garmin nüvi 250. How to add POI with POI loader or other program so that it will not replace speedcam POI-s I had there before.

If i add POI it will replace former ones and place new ones... But I wold like to remain former and add new additional POI-s.

Sincerely

Rein