Unfortunately I don't know of a way to put the item number in parenthesis.
Of course, using a manually typed note is the worst because if the item number changes then the typed number will not.
It's possible to create a balloon with no border, then create a note with just the parenthesis and group the two. However, that kind of sucks because maintaining relative position by grouping is somewhat unreliable in SW.
Considering the SW aspect only, the simplest thing would be to change your drawing procedures such that some other shape of balloon (hex, diamond, underline, etc) means "reference". Whether or not this is possible in your environment may be another story though...
Unfortunately I don't know of a way to put the item number in parenthesis.
Of course, using a manually typed note is the worst because if the item number changes then the typed number will not.
It's possible to create a balloon with no border, then create a note with just the parenthesis and group the two. However, that kind of sucks because maintaining relative position by grouping is somewhat unreliable in SW.
Considering the SW aspect only, the simplest thing would be to change your drawing procedures such that some other shape of balloon (hex, diamond, underline, etc) means "reference". Whether or not this is possible in your environment may be another story though...