You can use the DISM command to add drivers into an offline Windows image.
Copy your Windows Image into a folder of your choosing in that case we will use C:\temp and in this folder create a folder named offline and copy your drivers folder here as well.
Open up an elevated command prompt and use these commands:
Dism /Get-ImageInfo "/ImageFile:C:\temp\Windows 10 Enterprise\sources\install.wim"
This will tell you the index number and the name needed for the next step.
Dism /Mount-Image "/ImageFile:C:\temp\Windows 10 Enterprise\install.wim" /Name:"Windows 10 Enterprise Technical Preview" /MountDir:C:\temp\offline
This will mount the offline image be sure to change the /Name: to match the output of the previous command, optionally you could use the /Index: value instead.
Dism /Image:C:\temp\offline /Add-Driver "/Driver:c:\temp\raid drivers" /Recurse
This will add all drivers located in the raid drivers folder.
Dism /Image:C:\temp\offline /Get-Drivers
This verifies the drivers you have added.
Dism /Unmount-Image /MountDir:C:\temp\offline /Commit
This unmounts the image and commits the changes you have made.