In WinUAE select an A1200 or A4000 quickstart config. To be sure, go to the ROMs page and check that it has selected an A1200 or A4000 ROM, then go to the Chipset page and check that it has selected a chipset matching the ROM.
Now go to the Harddrives page, click on Add Harddrive, select your CF card, tick the Read/Write box and change controller to IDE0. The latter will connect the CF card to the internal IDE port of the emulated Amiga.
Now you can handle the CF card with Amiga software as if it was connected to a real Amiga (which means it uses scsi.device as driver).
To make all 7.87 GiB available you only need a capable file system, for example
Aminet - disk/misc/pfs3aio.lha
Note that 7.87 GiB means 8,455,200,768 Bytes. Most manufacturers would call this 8.46 GB which means that your 8 GB card is probably smaller than the limit. What I want to say is that it's not worth the hassle with scsi.device patches because the mentioned file system is sufficient for 8 GB.