How do I gradually change tempo in a Sequence?

SITUATION: I have this song that I did @ 100 bmp and at a certain point, I would like to gradually decrease the tempo to about 60bmp, then gradually bring it back up to 100 bmp.

QUESTION: Is this possible? If so, how?

Thanks in advance,
suenos

On the XL:

In your sequence, highlight the tempo and press OPEN.

Rest is pretty self explanitory, more info on page 37 of the manual 'Tempo Change Window'.