I installed the plugin: "AddFunc Head & Footer Code" to allow me to access the <head> section of the page. I chose this plugin as it allows me to tailor the <head> section differently of each page.
I added the HighSlide css and js to the head.
Next, I wanted to insert the HighSlide body in my page but had problems

So, I installed another plugin: "Insert PHP Code Snippet" which lets you add php code. Now, instead of adding the HighSlide body, I inserted the php code: echo "....HighSlide Body...";
And this kept those <p> tags from being inserted.
HighSlide worked now!