There are some XSS Vulnerabilities in FTD v3.7.3 and prior.
They will also be launched when sent as a mail to yourself or a victim.
Proof of Concept:
To make sure it launches, you just need to add a word or a normal character before your code.
Example: Hello !
If you ignore this and you send you mail without adding a character before your code, you could get this problem:
If you send '',
it'll become 'Alert(1);'.
This is because the program wants to correct the first letter, it will try to make the first letter a capital one.