Maintaining hyperlinks in locked form fields

Hoping someone can help - I have some form fields that we input with rich text, as the text itself is hyperlinked i.e. the name of webinar, which then carries a link to the webinar's registration page. 

However, we have a lock button that once the content is all input, locks those editable form fields, so the PDF can be distributed. Unfortunately it seems the hyperlinks then don't work - or sometimes do work, but only with a Ctrl+click, which isn't ideal for our customers. 

Any ideas how to fix? Here's the JS from the Lock button if that helps (it locks and then hides the button too):

for (var i = 0 ; i < this.numFields ; i++) { var f = this.getField(this.getNthFieldName(i)) ; if (f.type != "Lock-PDF") // do I have to change the word between " " with the name of my button which I put on my PDF? name of button is "LOCK PDF" { f.readonly = true ; } } this.getField("Lock-PDF").display=display.hidden;

Thanks!