Exotic robes put on VP in religious ritual (10)

I believe the answer is:
observance
'religious ritual' is the definition.
'observance' can be an answer for 'ritual' (I've seen this before). I'm unsure of the 'religious' bit.
'exotic robes put on vp' is the wordplay.
'exotic' indicates an anagram (an unusual form of the letters).
'put on' is a charade indicator (letters next to each other) (some letters go on or after others).
'vp' becomes 'vance' (I can't explain this - if you can you should give a lot more credence to this answer).
'robes' anagrammed gives 'obser'.
'obser'+'vance'='OBSERVANCE'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for observance that I've seen before include "... than in the ____' (said 4)" , "As a rule" , "ritual" .)
