I can kind of help you out with this, I use to work with BlackBerry for a bit.
How long have you had your hotmail account, if its an older account you can do this, but if its a newer one within the past couple years, you have to pay an upgrade to hotmail I think its 19.99. Then you can add the email through your Providers BlacBerry Internet service (BIS).
Here are the Internet links depending on your service provider
https://bis.na.blackberry.com/html?brand=telus
https://bis.na.blackberry.com/html?brand=rogers
https://bis.na.blackberry.com/html?brand=bell
Once there you can add on your email adress and password, should be pretty easy to set up.
Hope that helps