The freetds/DBD::Sybase should work, though I don't know how far the freetds project has come to implement the protocol.

Another approach might be to use ODBC on Linux and DBD::ODBC.
I know, there are several implementations of ODBC in Linux, but I don't know any by name.

Update: Have a look at the documentation of DBD::ODBC, Your question may be answered there.