Great question Mike, and as this appears to be your first post - Welcome to the Communities!
So, to address your question - Yes you can do this!
Indeed 7.2.2L1 did not support this, the support for this came about in 7.2.4L1 (Though I'd advise going to 7.2.5.1 if your environment will support it)
The reference for this is here:
Common aggregates between external and internal disks
I'm writing this with Chrome (and lack intelligent HTML editing power in the writing window - so I'll repost the table from IE or Firefox)
Thanks for your question Mike, and as for this working, I performed this very same function on a 2050 yesterday!
Christopher