Converting software RAID0 to RAID10

Hey!

I’ve just installed openSUSE on software RAID0 as RAID10 was not available as an option in the installer.

/dev/sda3 + /dev/sdb3 = md0

Now I would like to mirror this volume on /dev/sdc3 + /dev/sdd3 to make a RAID10 or RAID1+0, whichever name you prefer - I assume they are the same.

Surely this can not be difficult. Any suggestions?