On my host system I use a mounting program (for example, Daemon Tools Pro Advanced.. it doesn't have to be this product, any should do for this method), and then I select the virtual drive when defining the cd/dvd drive in the configuration of the vm.
For example in the following image you can see that Drive K: is a virtual drive, yet VMWare Workstation treats it as a physical drive. This method works with DOSBox as well.