I’ve never used the X-lite, but i can’t see how you can get dialtone on a softphone anyway. You generally enter the number you want to dial and then hit some kind of “send” button.
On hard phones, the dialtone is generated by the phone itself. Its only purpose is to show that it’s registered and able to make calls. Can you make calls from your hard phone? (Is it a hardphone or is it an ATA???) If you can, then there may be something you can configure to give you the dialtone. If you can’t, then there’s probably something wrong with the configuration either of the phone or of Asterisk (assuming the network side is functioning properly).
What make/model of hard phone is it?