Success wrapping present in what? (7)
I believe the answer is:
wherein
'in what?' is the definition.
(synonyms)
'success wrapping present' is the wordplay.
'success' becomes 'win' (I've seen this in another clue).
'wrapping' means one lot of letters goes inside another.
'present' becomes 'here' (both can mean in attendance).
'win' going around 'here' is 'WHEREIN'.
(Other definitions for wherein that I've seen before include "Inside which" , "A question of placing" .)