When setting up an e-mail program you specify a "return adress"/e-mail adress.
This will be the adresss used when people press "reply" and also what is visible when people read your e-mails.
So yes - it would be possible, if your ISP (freeserve?) has e-mail account (provides smtp server)
Then you should set up your account as normal, but instead of typing the e-mail adress you likely have gotten from your ISP, you type your hotmail e-mail adress.
Then you will send e-mails via your ISP, but replies should be delivered to your reply adress (hotmail).
This would also be how you would attempt to send from your e-mail program, in your original question. The problem is that you can't download e-mails from Hotmail (to my knowlegde) withouth using a web-based interface (web-browser).
So just to recap.
Set up your e-mail program with outgoing server (smtp) from your ISP.
The e-mail adress should be your "reply to" e-mail, thus after what you say - your hotmail.
POP3 is rather insignificant, because if you only wish to use your hotmail, you would not use your e-mail program to download. But fill this out with your ISP information.
For instance my own e-mail program is Outlook. I have one ISP but 4 other services providing e-mails.
All e-mails I send go out via my ISP smtp server, but I download from 4 differnet POP3 accounts, and subsequently have 4 different "reply to" e-mail adressed connected to each relevant e-mail account setting.
I hope this made sences, because it can quickly become a tad technical
Otherwise - I'll try to find some screen shots of settings (on english - run danish version's myself, so names differ) to see if that can help you?