sendmail problem - bypassing dsbl.org for one IP

[jamie]

one of our virtual hosts connects to our server with a tiscali dialup connection.

unfortunately the sendmail rule:
FEATURE(`dnsbl', `list.dsbl.org'.....

detects him as a possible spammer and won't allow him to send mails to any external domains (local delivery is fine - but of little use for his business)

i have disabled the dsbl.org list temporarily but am now inundated with spam, so i have to enable it again soon.

is there a way to allow access for his internet account, which appears in the maillog as:

relay=212-7-42-61.DialUp.tiscali.es [212.7.42.61] (may be forged)

whilst still enabling the blacklist feature?

the only other option will be to ask him to change his provider :-(

many thanks