One more thing.
When I was talking (email) to one of the Hotmail admins some time ago, he told me NOT to use any words with TEST in the email, as it would also set some "flags"
small quote from the email:
Please confirm that your emails comply with MSN Hotmailís technical standards.
This information can be found at: http://advertising.msn.com/adproducts/Email_TechStd.asp.
Also, one thing I see that you have updated your SPF record.
This will not usually get your mails filtered but since we do filter based on reputation of the senders domain rather then IP address, this will positively impact your reputation.
This will take 24-48 hours for it to replicate throughout MSN Hotmail.
After that time period please send us three mails to firstname.lastname@example.org.
Remember not to include the word "TEST" in the subject line or in the body of the mails.
Also, try to make the mails exactly the same as the ones that would originate from your mail server.
Once you have done that please reply back to us with all 3 of the subject lines of the mails.
Thank you very much and I appreciate your time and effort I understand that this type of issue can be frustrating especially from your standpoint.
MSN Hotmail Domain Support