Hi Lorax, this is how I ended up fixing this issue - I wanted 3 promotions side by side on the same row so I ended up putting the shortcode into a table to do the formatting I wanted.
Here is what I did:
1) Created 3 different (or in your case 2 different) promotions using the Promotions section of wordpress - you'll need 2 or 3 'sliders' and however many pics/slides you want per slider would be how many 'promotions' you need. (Note: I'm using the wording as it is used in wordpress promotion plugin).
2) Figure out how big you want each promotion/slider to be. In my case, I did 960 total width of my page, then subtracted out the spacing I wanted in between each promotion/slider and also subtracted out the padding on each side of the row I wanted (in my case, I wanted 3 pixels in between each slider as spacing and 5 px padding on each end of the row). So mine ended up being: 960-10 (5px of padding on each side of the row) = 950 -6 (spacing between sliders) = 944; each slider needs to be 314
3) Next, within WordPress, I went to 'Appearance' then 'widgets' (note: I have a ProPhoto4 add-on purchased/installed so experience may be different than yours.)
4) I have a section called 'Bio Area Spanning Column' on the right side that I added an html/text widget to. Yours may say body or another section of the site where you want the promotion to show.
5) Here is the table coding I added into my html/text widget:
[promoslider id="children_slider" category="children_slider" width="314px" height="471px" time_delay="8" pause_on_hover="pause"]
<td>[promoslider id="weddingevent_slider" category="weddingevent_slider" width="314px" height="471px" time_delay="8" pause_on_hover="pause"]
<td>[promoslider id="places_slider" category="places_slider" width="314px" height="471px" time_delay="8" pause_on_hover="pause"]
Hope this gives you some example. You'll probably need to tweak for your needs and also what you see in your WordPress Appearance->Widgets area.