Spectrum has 3 ways to capture configs in NCM:
1. TFTP and SNMP
2. SSH and FTP
3. Scripting
I think out of these options you should be able to get it to work.
It also depends on if you have access to the devices via TFTP.
Typically for option 1, you need to be able to send an SNMP request from the Landscape Server to the device, and it tries to send the config to a tftp server.
If you can't get Option 1 or 2 to work, you could use perl to use the SSH module and capture the config that way. This should be the last resort as the others are more supported.
Also ensure firewalls/ACL's have been modified for all comms between the Landscape Servers and the Device itself (in BOTH directions!)
Regards,
Frank