[Exim] errors_to and syntax errors

Hi,

I have an Exim 4.04 router specified as:

virtual_aliasfile:
driver = redirect
domains = +vipdomains
file_transport = address_file
data = ${lookup{$local_part@$domain} lsearch{ALIASESDIR/vipaliases}}
errors_to = postmaster@$domain

Everything works great, except that syntax errors in the alias file
that is retrieved into the data= portion seem to be ignoring the
errors_to statement. Because non-mail-admins have access to these
particular aliases files, syntax errors do occur occasionally.

I don't want to skip syntax errors - I do indeed want an error to
occur. However, I would rather have the error go to
postmaster@$domain rather than to the original sender.

But, Exim 4.04 seems to be ignoring "errors_to" on syntax errors.

Is "errors_to" not applicable in this instance?

Regards,

Dean A. Brooks
dean@???