I think what you have to do is to create the jpg.file of the text below or above the line.
To insert the jpg.file of the line, though it is not exactly the same as what you want,
First, you have to make a line, for example with Keynote, a presentation software.
Then, save the page of it as a picture. But, as the whole page of Keynote became a picture, so
you have to cut out the line part with for example Toyviewer. And, after saving it as a jpg file,
you can use View->Header Footer in the menu bar of maple. And, click the 'Custom Header' tab there, and
after selecting the leftiest box, you can click the 'Insert Picture' and chooze the jpg file you created above.