How to install Windows 7 on a partition of an already partitioned GPT disk?

Question

Windows

I have a GPT disk with Debian (Deepin) installed:
#1 - fat32 (/boot/efi) 300MB [/dev/sda1]
#2 - ntfs 100GB [/dev/sda3]
#3 - fat32 (/) 360GB [/ dev/sda2]
I want to install windows on partition #2. Windows does not want to install because it is GPT.
How do I put Windows on a partition without repartitioning the disk?
As I understand it, you need to put the image of the working Windows partition on the partition and push the Windows bootloader into /boot/efi. But how to configure grub to do this?
====Upd====
I solved the problem like this: I created a table on a GPT flash drive, an ntfs partition, uploaded files from .iso there, pulled it out from sources/install.wim:1/Windows/Boot/EFI/bootmgfw.efi and moved to /efi/boot/bootx64.efi