Good Day Dhet87,
Thanks for posting.
There is a tick-box option in the dialog called 'Include Perimeter Beams?' for the I-Joist option which will draw the same beams (type & size) around the perimeter of the shape drawn. However if you want a different beam type and/or size for these beams, then it's recommend to use the Beam Tool
in the current version.
Could you please try this and let me know how it goes?
Thanks and have a great day.