I get what you mean - you're having troubles with the Enter button on the actual Add an Entry page, correct? What I normally do if this becomes a problem is click on the little button above the entry box (where you type in the entry you want to post) that has little letters that spell "HTML." It will open up a pop-up where YOU control the coding of the entry. First, make sure the box at the top right next to "Wordwrap" is checked. Then, type out your entry.
Where you want there to be one line skipped, type <br>
Where you want there to be two lines skipped, type <br><br>
Then click Update, and it will bring you back to the normal Add an Entry page. All you have to do is click Publish, and things should work as you want them to. :]
Hope this helped!