I have such a setup. Here's how it works, though I am not sure if you have a router, but I do...
1. LAN on computer cable to router.
2. router cable to DSL modem WAN
3. DSL PHONE line on modem to DSL side of filter that goes to your wall jack.
4. Normal phone line side of filter on your wall jack to the LINE input on your v90 Fax/Modem on the computer.
5. Phone input on v90 Fax/Modem on computer to the telephone itself.
That's my setup. My telephone is actually a Uniden digital cordless phone/answering machine system. This way, you can use your phone, fax/modem for faxes, etc. and HAL can dial for you and you just pick up your telephone and talk when the party connects.

I admit I haven't actually used HAL's dial feature. I almost did, when he misunderstood what I said and the word "call" ended up in the text box when I said something else in speech recognition mode.

I managed to stop it as I noticed an icon in my system tray and could stop the call. However, now whenever the phone rings, that same icon pops up in my system tray and I hear not just my phone ring, but also the COMPUTER makes a phone ringing sound. [:0]