Modifying RAID configuration with already activated Open-E DSS

We have Open-E DSS V6 4TB b4622 64-bit which is activated and registered for almost one year.
It is installed on LSI SAS RAID10 2GB boot volume. The rest of RAID10 is used as another RAID10 volume for data.
RAID10 is consisting of 6x SAS/750GB/HDDs so we have about 2.1TB space in this RAID10.

We need more space on RAID volume (4TB is limitied capacity regarding licence).
So, we want to completely reconfigure RAID10 into RAID5 or RAID6 with additional HDDs.
The goal is to have RAID5 or RAID6 with 3.5-3.7TB of capacity.

Now, the problem is that I have to completely reinstall Open-E DSS (this time, the latest b5626) on newly created and initialized RAID5 2GB boot volume.
So, I will enter existing PRODUCT KEY .
But, what shall I do with product activation since it is already activated once.

Shall I send new hardware stamp to (Activation key email) , or just use my original XML file for activating Open-E DSS V6 b5626 ?

Note: post edited ( remove the activation email, and put the (Activation key email) instead of it, to reduce SPAM

Yes, that is correct. Another activation is required since system medium has changed.
If you haven't changed f.e. motherboard as well you can try on-line activation too.