It seems that open-e doesn't accept partitions on a HDD but needs a seperate disk to be able to create a volume group. Booting from USB stick would work if that DELL stuff would accept anything and actually boot.

I will get new (of course old ones, but new to me ) PCs later and will try again then.

I know that normally noone would try it out on stuff that I use and I know that under normal circumstances it is a non existing problem... but oh well, that stuff is all that they give me for now.

Thanks for helping.