Well, It is not that easy to go directly from DSS V5 to V7.

First, please have a look to the following KBs:
http://kb.open-e.com/XSR-To-DSS-V6-Conversion_1183.html
And
http://kb.open-e.com/Upgrading-from-...S-V5_1113.html

The best and fastest way will be to save all the data to another backup storage, and set up the system from scratch with DSS V7 then copy back (restore) the backup date to it.

As the V7 is a 64Bit only, so the best to deal with 32/64bit is to format the old 32 as 64bit and copy the data back to it. With V6, we have a small update tool that allow 64bit system to deal with 32bit, but we still recommend the above steps(backup data, create from scratch).

Saving settings/configurations from V5 and applying them to V7 is not tested, and we are not sure if that can work with no issues or not.
Beside the RAID controller Firmware must be updated when dealing with the latest builds of DSS V6 or V7.