Changing to a directory with special character (@) fails

Version: 4.1.9 and 4.2.3 Beta
Windows XP SP 3, all updates (except september 2009) installed
SCP protocol
No scripting/automation, standard install of WinSCP
Full error message:
----- snip -----
Command 'cd "Bl@ck"'
failed with return code -1 and error message
invalid characters in scp command!
here:@ck"
try using a wildcard to match this file/directory.
----- snip -----

Steps taken: double-click on the remote folder named "Bl@ck" (it's a PHPBB3 style)
Server: Debian Lenny, scponly 4.8-4

There's another issue with the same folder when syncronizing folders, I think it's also related to the problem mentioned above.
The sync throws an error when trying the Bl@ck folder (but is able to skip and seems to show the correct changed files later):
----- snip -----
Command 'ls -la --full-time "/path/to/the/folder/PHPBB3/html/styles/Bl@ck"'
failed with return code -1 and error message
invalid characters in scp command!
here:@ck"
try using a wildcard to match this file/directory.
----- snip -----

I believe that this is problem of the scponly shell, not of WinSCP.

OK, seems to be so, didn't think of that.
Is there any workaround that could be implemented into WinSCP?
I read something about wildcards but am unsure if this could solve the problem.

G.Schuster wrote:

Is there any workaround that could be implemented into WinSCP?
I read something about wildcards but am unsure if this could solve the problem.

I do not know how. Wildcards are not an option for GUI client. Cannot you use SFTP?