Custom Lookup Dialog Box

Ok, I have 2 questions that I am struggling with. First, due to limitations of the built-in lookup dialog box, I have created my own. The form opens on cntrl+spacebar like its supposed to, and I can select an entry and click the OK button for it to be inserted into my primary form.

First question: like in the default lookup dialog box, I would like to be able to use the enter key to insert the value, and not have to press the OK button at the bottom of the form. I am a keyboard oriented person and hate to have to leave the keyboard to grab the mouse for this. I know this can be done, it just escapes me.

Second question: like in the default lookup dialog box, I would like to be able to type the first few letters of the entry that I am looking for and have the table jump, scroll, or filter directly to the entries that begin with those letters.

My form is simple, I created a blank form which is a modal dialog box style, on which I place a continuous table with fields that are populated by the values in a different table. (Site, City, State, Code) I want to be able to begin typing the site name that I am looking for and once found hit the enter key to select it and return it to my primary form.

Any help would be appreciated.
Thanks.