For those who are interested...

I use a curl to reboot two IPsec tunnel endpoints once a week, so that I 
can keep P1 renewals synchronized. See "Avoiding Dropped Connections 
 From Phase 1 Negotiations" on m0n0wall's Wiki:

http://wiki.m0n0.ch/wikka.php?wakka=AvoidingDroppedConnectionsFromPhase1Negotiations

There is another reason: I know exactly when my my PPPOE session will 
re-establish, even after a power loss. See my previous post for the 
details:

http://m0n0.ch/wall/list/?action=show_msg&actionargs[]=96&actionargs[]=31

Of course this won't fix any m0n0wall's bug, nor provide any useful 
debugging info...

-- Vincent