How to write in an application field that is not scriptable?

Dear Scripters:
I would like to say how is it possible to fill a text field inside an application that does’t have dictionary. That to say, I can, for example, click the menu item doing:

tell application "FeedMe"
end tell
tell application "System Events"
	tell process "FeedMe"
		click the menu item "New Item" of the menu "Feed" of menu bar 1
	end tell
end tell

But, I don’t know how is it possible to write a text in the text fields of my application!
Anyone knows how does it work?
Thanks in advance!

I take it you’re talking about this FeedMe, profesoralex - in which case, try something like this:

set linkText to "http://some/link/"
set descriptionText to "This is a sample description..."

tell application "FeedMe" to activate
tell application "System Events"
	keystroke "n" using command down
	keystroke linkText & tab & descriptionText
end tell