Making one's name as a writer (7)
I believe the answer is:
Here is my best explanation:
'making' is the definition.
The definition and answer can be both to do with communicating as well as being present participle verbs.
Perhaps you can see an association between them that I don't see?
'one's name as a writer' is the wordplay.
I cannot really understand how this works, but
'name' could be 'si' and 'si' is found in the answer.
'writer' could be 'i' (the person who is writing these clues) and 'i' is located in the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for signing that I've seen before include "Autographing", "recent addition to team", "means of communication?" and "Writing".)