backslash in addresses?

[Aleksandar Milivojevic]

If an email address starts with backslash ("\"), sendmail will not 
perform alias substituion.  I'm attempting to use that feature inside my 
Sieve script (generated by Horde's Ingo application) as follows:

if true {
    redirect "\\alex at milivojevic.org";
    keep;
}

However, I'm getting an error from timsieved:

script errors: line 7: address '\alex at milivojevic.org': parse error, 
unexpected $undefined.

Does this means Sieve does not support "backslashed" addresses, or my 
Sieve script manager program generated errornous script?  If later, what 
would be the correct way to escape backslash that is part of email address?

Thanks,
Aleksandar Milivojevic
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