how to change dynamic text and keep format

Hi,
I hope this is an easy one to explain to me.

How do I change dynamic text so that only the selected text changes?

Currently I have imported text into a feild of s template to replace the jibberish the designer put in.

I lost my textformatting. I figured maybe I did not import in the right format and would reformat in Flash. Howeve,r when dymamic text is selected format in flash, if I highlight and select BOLD, the entire body of text changes as well. I only wanted the highlighted section to change.

IF I switch back to static text I cand format as normal, but I loose my scroll bar. It no longer works.
After I adjust the text if I change back to dynamic from static, I loose all that work. The text goes to a uniform look.

How can I import text and have the formatting remain and why does all the text change, when it is dymamic text even though I have text highlighted?
Why does the scroll bar not work in static text?

I am new to Flash and have been struggling to figure things out on my own so I am not seeking some help to speed things along.

I am using Flash 8 Pro and bought a template which I am learning how to alter. So any help will be appreciated.
Thanks!