Using PHP mssql_init/bind for sending Unicode to Stored Procedures

I know this isn't totally FreeTDS' issue, but I was curious if anyone 
else has had experience/success with using PHP's "stored procedure" 
support for MSSQL, as it seems like it'd be a cleaner/safer way than a 
straight EXEC call...

In any event, perhaps it's simply a lack of NVARCHAR in the php_mssql 
library, but I cannot send UTF8 data to SQL Server using 
mssql_init/bind/execute - yet it's not a general fault in my setup, as I 
can "EXEC blah N'<UTF Text>'" just fine.

Just not supported (yet), or am I missing something?

Thank you!
-Jason Young