It's not possible to attach different sizes of Harddisks to a RAID 0. This results in capacity failures (have a look at the screenshot).
Thats true for Hardware RAIDs but not for Software RAIDs e.g. Linux Meta Devices.

Used version: 0.9.9-5
tried to join 2 SATA Harddisks with Partition: "Linux RAID Autodetect" (you should add this as partition) to a metadevice called md1.
One HDD got 1 TB and the second got 2 TB the resulting RAID 0 md1 was 2 TB but should be 3
see attachement

but with JBOD it would work

used Version is 0.9.9.5
added 4 files in template but during Object creation out of a template only the first added file will be taken.
this worked under 0.9.9.4

Hi,
I've added a file in a Switch-Template under Version 0.9.9.4 and now in Version 0.9.9.5 but the listed description and version strings for that files are wrong under 0.9.9.5. Have a look at the attached image.
Mail me, if any other information is required.