Mount with mount -t userlandfs -p sshfs .... You can pass arguments to the client FS by adding them to the argument of the -p option after the client FS name (as one string, like: -p foofs arg1 arg2). To get debug output run the userlandfs server manually in a terminal before mounting (userlandfs_server sshfs). You'll also have to do that, if the client FS requires input like the password for sshfs.
echo password | /system/servers/userlandfs_server sshfs
mount -t userlandfs -o 'sshfs user@server:./ -o password_stdin' /mnt