Hello Peter,
USBX device and host stacks are almost fully independent of one another. In fact, on all of the Renesas S7G2 kits, host and device interfaces are hard-wired to separate USB controllers (USBHS and FS, respectively). I'm attaching a simple example of USB CDC-ACM device with USB Mass Storage Host running on DK-S7 kit. You should be able to adapt this project to work with SK-S7 (make sure the VBUS polarity is set to active low on that board): (Please visit the site to view this file)
On PE-HMI1, this project should work without any changes.
Regards