This reply from David Wang (MSFT) on the Google groups with some interesting information:
You need to turn pinging back on. Report unhealthy depends on failing the ping
(and failing the ping is what triggers IIS to recycle the worker process). Enabling
pinging should not affect your other recycling options, since all you needed to do
was turn off all the time-based recycling metrics -- from a default installation,
all you need to turn off are "Idle Timeout" (15 minutes by default) and "Periodic
Recycling" (29 hours by default).
Regarding - responseRestartDeadlockInterval and responseDeadlockInterval -- there
isn't anything comparable in IIS6 because ASP.Net is using the "report unhealthy"
mechanism to get IIS6 to recycle itself. How the interval is configured should be
specific to ASP.Net.