[nznog] MX2 with SPF

Hi all I've been having a problem lately of getting far too much spoofed email being sent with my email address directly to our secondary mx which tries delivering it to our primary which 550's it (unknown user) and thus I get the bounce. To solve this I thought about doing the SPF thing for our domains, but this wouldn't solve the above problem unless the secondary mx does SPF as well. Because of various reasons we are using an ISPs seconday mx server for our domains, and thus have no control of that servers configuation. What i'm really asking is, does anybody know of someone selling a secondary mx service with SPF enabled? Cheers Joel van Velden