You can put your password in a text file stored securely in your private data folder and use the <INC> hot code to have Asutype call out the file content at run time.
For example, I created two text files under the "My Documents" folder to store my user name and password for my Facebook login:
Since they are in my private data folder, no one except me can have access to them.
In Asutype's Shortcut Editor, I created a shortcut with the "Hot text" as "fb//" and the "Content" as:
As illustrated in the screen shot, the shortcut only shows my file names, not my actual login name and password. At runtime, when I type "fb//" to expand the shortcut, Asutype will read my login name from the file "facebook-username.txt" and my password from the file "facebook-password.txt" and put them into the appropriate boxes for me.