SunSSH should support EOW extension
From OpenSSH 5.1 release notes:
ssh(1) and sshd(8) now support signalling that channels are half-closed for writing, through a channel protocol extension notification "firstname.lastname@example.org". This allows propagation of closed file descriptors, so that commands such as: "ssh -2 localhost od /bin/ls | true" do not send unnecessary data over the wire. (bz#85)
SunSSH should support this as well.