12.1 RC1 Net install apparently not working in a new Virtualbox VM

Hi,

I tried several times to install 12.1 Mx, then 12.1 RC 1 from the net install CD, but every time, it fails to get the info from the repositories, in spite of the fact that I do have given the right parameters manually for the network adaptators including DHCP and proxy settings.
Furthermore, if I make a mistake in the location of the repositories for OSS, I get an error message that I do not get when I remove the error.
The network card is set with NAT and I have several other VMs working the same way (including one with opensuse 11.3 as guest).
VBox version is 4.1.4. Host is opensuse 11.4.

Did someone succeed with net install of 12.1 in a virtualbox VM ?