complicated routing q

[Gregory Edigaroff]

Hello,

I have something like this:

ppp1 ------
                Router (FreeBSD) ----- Network
ppp2 ------

Where ppp1 and ppp2 are ppp links looking at the same provider.

I would like to implement a load balancing and backup over ppp links.
I thought that in order to achieve this I need to add a second default 
route i.e. something like:

route add -net default $ppp1-ip
route add -net default $ppp2-ip  

this doesn't work.
What can I do?

-- 
With best regards,
	Gregory Edigarov