I believe that's called Mac OS X 10.7 Help- Use Back to My Mac
BTMM will also give you access to the files on the TC.. The last reference Kappy gave has info on that.
Clearly states you can do it.
Requirements for using Time Capsule or an 802.11n-based AirPort base station with Back to My Mac and the iCloud service
- Time Capsule, AirPort Express (802.11n), or AirPort Extreme (802.11n)
- A compatible, external USB hard drive* connected to AirPort Extreme (802.11n) for remote file access. (An external USB drive may optionally be used with Time Capsule for additional storage.)
I believe you will find the setup difficult unless the TC is the main router to the network.. although it doesn't state that.