Hi LaCrews,
There is no 'Use my preferences' flag in the function signature.
Did some digging it is possible to leave the value blank....and still have it send an email.
What you need to do is for the user that you are using the credentials of to validate your api access....in step 2 of 10: Email Setup. If you uncheck the 'use default email server settings?' option and enter the email server credentials there. Then if you leave the email server string empty in your api call it should use send an email using those credentials.
Dave