Resizing of a LVM partition

[Markus Lindholm]

Hi

I have a hardware RAID-5 that I've just expanded with two disks,
parted shows the following

(parted) print free
Model: HPT DISK_5_0 (scsi)
Disk /dev/sdc: 1250GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size   Type     File system  Flags
 1      32.3kB  750GB   750GB  primary
        750GB   1250GB  500GB           Free Space

on top of partition 1 I currently have lvm and ext3. Now what I try to
do is to expand partition 1 and then a pvresize in lvm. But parted
will not let me resize sdc1 instead it complains "Could not detect
file system."

I'm not sure parted supports resizing och lvm partition or whether I'm
doing something wrong here. I guess I could create a second partition
from the free space and include it my volume group.

What would be best practice?

/markus