Expand raid 5 (change 1TB into 2TB drives]

Hello everybody,

I need some help with my raid 5.
I have this configuration on my Ubuntu Linux 9.04 home server that I use as a second Backup server.

/dev/md0 Yes Mirrored (RAID1) 9.31 GB /dev/sdg1 | /dev/sdh1

/dev/md1 Yes Mirrored (RAID1) 1.86 GB /dev/sdg2 | /dev/sdh2

/dev/md2 Yes Mirrored (RAID1) 221.71 GB /dev/sdg3 | /dev/sdh3

/dev/md3 Yes Redundant (RAID5) 3.64 TB /dev/sda1 | /dev/sdb1 | /dev/sdc1 | /dev/sdd1 | /dev/sde1

All the drives in my raid5 (Software Raid) are 1TB SATA II drives. Now I want to “upgrade” to 2TB drives.

I have the following questions:

Can I do that with the webmin Interface?
What is the best way to do this?

I hope somebody can give me some hints. Until now the server worked excelent whit the raid 5.

Greetings from germany.