Note that $1 here is the nickname you are sending to, and $2- is the text you are sending.

So your "user"-specific message in the above would be something like:

Code:
{Private message to $1 $+ } $2-


(i.e.
Code:
/alias notice notice $1 {Private message to $1 $+ } $2-
)

The $+ is needed to join the identifier to the following text without an intervening space. $1} would be misinterpreted as the identifier called "1}", and not as $1 followed by a }

HTH