How to Add Outbound ICMP Firewall Rule on Netgear DG834G

Does anyone know how to allow outbound ICMP traffic on a Netgear DG834G
router without simply allowing everything outbound?

Basically, I've tightened security on the DG834G to only allow outbound
those services I want users to run (eg. HTTP, DNS, etc.) through a series of
firewall rules. This works absolutely fine. However, I also wanted to allow
outbound pings, tracert, etc. and I cannot see how to allow outbound ICMP
traffic. If I try to define a new Service I only get the options of service
type TCP or UDP.

Any ideas?

Thanks, David