Grant IIS Express permission to access network dri

I have a Windows 7 virtual machine in VMWare that I'm using to develop ASP.NET MVC 5 Web applications with the default IIS Express server. I like to keep my projects saved on an external hard drive which I can access in the virtual machine through a shared folder / network drive. However, when I run my applications, IIS Express cannot access my web.config files in the project directory. It's looking in the right folder so I'm pretty sure this is a permissions issue. How can I grant IIS Express file access to the files on my network drive?

Things I've tried

Running Visual Studio as an administrator
Setting iisexpress.exe to always run as an administrator
Looking around in the applicationhost.config file
Attempting to set write permissions on the network drive (right click on the drive and go to properties but no "Security" tab available)
A few other things that I can't remember that I tried during the hours of searching for a solution

Known last resorts that I'd prefer to avoid

Copying the project files from the external hard drive to the VM's storage space and vice versa
Running the projects on a full IIS server

Other things to know

Using Visual Studio 2013 and MVC 5
Using IIS Express 7.5
VMWare Workstation 11
The virtual machine is also on the external hard drive, so I can't connect the usb to the guest, I need to access the rest of the hard drive through shared folders (although doubtful, maybe partitioning the hard drive would fix this?)
Guest OS is Windows 7 Professional
Host OS is Debian Jessie RC1
External HDD is formatted as NTFS, although it shows up as HGFS on the network drive
I can read and write to files on the network drive, it's just IIS Express that is having trouble

VMware/VirtualBox's shared folder between the guest and host is kind of using mapped drive feature of Windows. However, neither IIS nor IIS Express supports mapped drives. If possible, use a sync tool, such as Dropbox, or simply Git to share bits between the two.