boot hangs on network interface configuring

When upgrading to Karmic Koala it configures /etc/network/inrfaces in a way that makes the boot hanging forever, by changing it back to what it was before it boots properly but I have to reconfigure the internet with pppoeconf manually every time, one work around I thougtht would be setting up a command on the start up aplication to configure the pppoeconf and changing /etc/network/interface back to original, Does any one know the commands I have to use.

*on pppoeconf I need to put user and password

****this is how /etc/network/interface looks like

auto lo
iface lo inet loopback

auto eth0
iface dsl-provider inet ppp
pre-up /sbin/ifconfig eth0 up # line maintained by pppoeconf
provider dsl-provider

auto eth0
iface eth0 inet manual

****this is how it should look like

auto lo
iface lo inet loopback

any other Idea is very welcome, thanks