Cursor Positioning in Multiline Textbox

I could use a little help.
 
I have an Adobe Acrobat PDF that has a multiline textbox in it. I fill the textbox with data in Visual Basic and launch the PDF.
 
When I tab to the textbox Acrobat puts the cursor at the end of the text.
 
I have been asked to place the cursor at the start of the text in the multiline textbox.
 
I have tried Javascript in the on focus event of the textbox and it does not even seem to be being executed. I have intentionally put compile errors in the java script. The errors did not result in any kind of error or warning.
 
I am running Acrobat Pro 8.2.6 in a Windows XP environment using Visual Basic 6.
 
I would really appreciate it if someone could let me know how this is done.