kinternet cannot set route

I have now have an ethernet router connected ADSL connection, and I have set this as the default route. However I still need to be able to dial into my dial-up ISP via modem to access certain servers. I have set up kinternet via YAST to connect to the provider, and the connection is established when I click on the icon. However I need to set specific routes via this interface, so I set up an /etc/ppp/ip-up script containing "ip route" commands, but these fail because the user (not root) from which I click on kinternet does not have permission to set routes. What is the correct procedure to automatically establish these routes when the PPP link is brought up? (and drop them when the link is closed)