Some good news!
I have just stumbled upon this comment:
https://www-secure.symantec.com/connect/blogs/what-really-makes-market-leader#comment-9852901
VMware went GA with vSphere 5.5 around October 2013 and we generally attempt to release support within about 90 days of GA.
That thread you cite was about Backup Exec. Backup Exec 2012 users received this support in SP3 on November 19, 2013. BE2010 will not support vSphere 5.5.
This timing put us in an awkward situation for NetBackup, since v7.6 was in the final release stages when VMware went GA. NetBackup 7.6 went GA in late December, so we built a special vSphere 5.5 patch for early adopters. The patch is available through our SymBeta download and went live January 31, 2014. If you are an early adopter and very interested, please sign up and we'll be sure you get your hands on it. If you can wait just a bit longer, the upcoming April NetBackup 7.6.0.2 maintenance release will include the patch and be widely available.
Note that vSphere 5.5 will not be supported for NetBackup 7.5.
The patch also applies to appliance customers. Enjoy!
This seems like a good place to mention the vSphere plugin available for NetBackup 7.6 too.
