Hello,
Your correct on both points.
The official RC from MS has a patch for the permission problems, and
Homegroup is ONLY used when connecting two or more systems that are running Win 7, it cannot be used for connecting dissimilar OS's (at least not so far as I can tell)
This is mentioned when you first begin to setup Windows, it does state that it's only for connecting to other Windows 7 PC's
Operating System Windows 7 64-nit
Computer Type E-Machines (Customized}
CPU Type and Speed AMD Athlon™ II X2 250u Processor 1.60GHz Max 1.60GHz Ext 200MHz Cores 2 Threads 2
Motherboard Chipset eMachines
System Memory Type 6GB DDR2 RAM DIMM Speed 266MHz
Video Card Type and Speed NVIDIA GeForce 8500 GT 512 MB memory with HDMI out
Computer Monitor Vizio 26" HDMI monitor
Hard Drive Seagate ST375052 8AS (500GB) and WD25 00AAKS-00VSA (250GB)
Optical Drives HL-DT-ST DVDRAM GH41N
Network Adapter NVIDIA nForce 10/100 Mbps Ethernet
Anti-virus Software PC Tools Spyware Doctor with Anti-virus
Computer Skill Level Certified Professional
Windows Experience Index 4.5