Writing Unicode to MS Sql on Linux

Following the instructions on getting Rails to work with MS Sql on
Linux worked as far as reading unicode data from the database.
However, when I tried to write UTF-8 data that is non english the data
became a series of ??.

Is there any solution or configuration required to write unicode data
to MS Sql so that it will not try to apply a code page to the data and
corrupt it in the process?

If I can modify the sql query constructed by Active Record to insert a
N prefix to data value in the sql string, the problem may be solved
but how do I hack into Active Record to do that?

For example

insert into mytable values ( N'unicodedata' )