It's look that your router can't do what you want ...

This Asus does not look to have the same stream ability of the Lynksys one.. Not sure you can do it. it said that he have an ease to stream, but no mention directly from a USB drive , they said the USb can be use for ftp or printer.
look at this one it have a build in media server
Linksys by Cisco Wireless-N Broadband Router with Storage Link WRT160NL
The
Storage Link feature lets you connect a hard drive or flash-based USB storage device directly to your network to easily add gigabytes of storage. Access your music, video, or data files from anywhere within your network. Built-in DLNA 1.5 compatible media server streams to PCs or UPnP AV digital media adapters
.