mbtel,
Pay very close attention to what tito1411 said - Having NetBIOS ports open on the internet is an absolutely horrid idea. Not only are you making any shares that are not passworded completely visible, but it opens up an attack vector.
Netbios allows you to re-try associating with no 'penalty delay' or lockout for incorrect password attempts. Incorrect logins MAY be logged - if logging is turned on, and if someone is actually checking those logs. This means an attacker can run a simple brute force against your system all day, every day, and nobody is going to notice.
They might not like the idea of having a VPN, but it is their safest option. Otherwise, as rustynails said, FTP is always a (less secure but ) viable option.
Have a day!
Tod.
ps.
Comcast does block those ports, and now you know the reason(s). It's a Good Thing (TM).
