Connection to IBM mainframe with Implicit SSL

I am trying to connect to an IBM mainframe that is running z/VM 5.1 with its FTP server working through the IBM SSLSERV protection mechanism on port 990. I can make the connection but itnever gets the list of files in the default directory.

Has anyone successfully used SmartFTP to connect to this kind of a server?

Here is the logfile:

SmartFTP v1.1.985.6
Resolving host name vm1.hqadmin.doe.gov...
Connecting to (vm1.hqadmin.doe.gov) -> IP: 205.254.145.35 PORT: 990
Connected. Exchanging encryption keys...
Session Cipher: 128 bit RC4
SSL encrypted session established.
Connected to (vm1.hqadmin.doe.gov) -> Time = 391ms
Socket connected waiting for login sequence.
220-FTPSSL IBM VM Level 510 at VM1.HQADMIN.DOE.GOV, 10:05:29 EDT THURSDAY 2005-06-23
220 Connection will close if idle for more than 5 minutes.
USER u8803kt
331 Send password please.
PASS (hidden)
230-U8803KT logged in; working directory = U8803KT 191 (ReadOnly)
230 write access currently unavailable
SYST
215-z/VM Version 5 Release 1.0, service level 0402 (64-bit)
VM/CMS Level 19, Service Level 401
215 VM is the operating system of this server. UNIX list format is active.
FEAT
500 Unknown command, 'FEAT'
PBSZ 0
500 Unknown command, 'PBSZ'
TYPE I
200 Representation type is IMAGE.
REST 0
500 REST is only allowed for block or compressed mode.
PWD
257 "U8803KT.191" is working directory (ReadOnly)
PROT P
500 Unknown command, 'PROT'
NOOP
200 Ok
NOOP
200 Ok
NOOP