setup-storage: resizing ntfs

[Andreas Heinlein]

Hello,

I have a question about resizing with setup-storage in general and
specifically regarding ntfs. We currently have Windows-only machines
with 12GB sda1 (primary, C:, NTFS) and the rest sda2 (primary, D:,
NTFS). We'd like to keep sda1 as it is and, if possible, resize sda2 to
make room for a new sda3 which will contain the FAI/Linux installation.

I currently have:
disk_config disk1 preserve_always:1,2 disklabel:msdos bootable:1
primary   -   0   -   -
primary   /windows 10240-81920:resize   ntfs   -
primary   / 20480   ext3   rw

I tried experimenting with resize in the disk_config line and/or the
partition; I have installed ntfsprogs into the nfsroot, but I cannot get
it to work. Specifically, setup-storage tells it is retaining sda1, but
then always tells me the disk is too small. Is this at all possible?

Thanks,
Andreas