This posting means trouble in China (7)
I believe the answer is:
mailing
'this posting' is the definition.
(I've seen this before)
'trouble in china' is the wordplay.
'trouble' becomes 'ail' (synonyms).
'in' is an insertion indicator.
'china' becomes 'ming' (type of china).
'ail' going inside 'ming' is 'MAILING'.
'means' acts as a link.
(Other definitions for mailing that I've seen before include "Sending by post" , "Dispatch by post" , "Posting" , "Sending a message" .)