The simplest solution is to just share them with us in the support ticket. Our web interface is secure so you don't have to worry about your server credentials being leaked. We have also added a checkbox labeled Contains Sensitive Information which prevents the text being sent in your ticket note from appearing in any plain text E-Mails - you and your team members must sign in to the customer dashboard to view the message.
You are free to change the credentials after we are done assisting you if that works with your security policy.
If you are uncomfortable leaving that info available in a past ticket (we can't erase them), there are web services available for providing one-time, password-protected links to your sensitive text. Below are just a few of the options.