[Exim] string expansion problem while lookup

hi,

i want to use in my acl:

deny_senders = ! ${lookup pgsql{select name,dom from address
}{$name@$dom}}

as an expression to verify the senders against a valid list....

but the variables $name and $dom did not exist .... i got failures...

how can i do this? i tried also extracting:

deny_senders = ! ${lookup pgsql{select name,dom from address }{
${extract{name}{$value}}@${extract{dom}{$value}}}}


but i think value is overridden by the firt extract... i dont know,
please help.....

*my head is about to explode*
volker