Question about Outlook Express

Up until today my business partner and I have both been able to access my hotmail account through live.com. She is geographically located in the USA whereas I am in AUS. This has never been an issue and has been occuring for years without setting off any security or red flags. Today I log in, to have the message showing that someone else has accessed my account and I'm required to have a code sent to my backup email and then my password reset...this is all well and good in theory, however the issue is that I KNOW that someone else has accessed my account, she has always accessed my account, that is the whole point. But now, this is not possible just out of the blue, and there is no option to disable this stupid auto detect security system, which now prevents us both from logging into the same account.

Now ordinarily this wouldn't be an issue if it was just a regular email account however it is very complex, set up with multiple folders for various emails, coming from our webstore, ebay, paypal and our suppliers. Once an email comes in and one of us answers/messages/deals with the email, we mark it as read and move it to another folder, so when the next person logs in, they know the email has been dealt with appropriately. If we use an email application to get the emails, we do not have this ease of use to quickly login and tell what has been handled and what is awaiting our individual attention.

I sent an email to microsoft support as it seems obvious that the only people that would be able to resolve this is the microsoft technical team who would have to make some kind of exception rule to my account that would allow her ip to access my email without setting off any red flags, however I've been told to write this support thread, so here goes, even though I have the feeling this will not resolve the issue as this is a community based forums where you guys don't have any kind of support access I require to resolve this issue.