I tested my friends Vita, with fw 3.65 permanent enso installed from 3.60, i can confirm that indeed it signs in and you can download your games from the store and sync your trophies, just after you update the spoofing version and reboot the device.
My 3.60 fw Vita still won't pass the sign in screen. Guess i'll have to move on to 3.65 Enso.
have you removed your DNS settings/reverted back to normal? only thing i can think of at this point....
also have you tried the below? It's not Vitaupdateblocker that is installed on your Vita, it's a seperate program installed to the PC that allows you to connect to the PSN store without an update request: