[exim] X-originating-IP

I'm getting more and more spam from webmail sites like hotmail, and i
was wondering if it was possible to write an acl to check the
X-originating-IP header against blacklists. i thought it would be a
simple task, but i've failed. perhaps somebody could clue me in :-)

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/Mvh. Peter Lindberg - Fiber.nu
+46 70-2758590 / uin:1059030