Well switches use that lightswitch method of 0 or 1.
0 being the cleared status and 1 being the set status.
To put it simply, using a deathcount as a switch is just a matter of using the condition:
Deathcount of "unit1" = 0 for cleared and
Deathcount of "unit1" = 1 for set.
Of course, you can always use any amount as the set variable... it's whatever floats your boat.