RMA Texture Parameter in Material Instance

Hi all,
I’ve been trying to develop a master material for my assets and managed to parameterising aspects of my material. However, after packing my Metallic, Roughness and AO maps into RMA format, I have lost the ability to input my RMA texture in the instance. Any assistance would be greatly appreciated.I have included the shader in an attachment below and just requires a copy and paste from the text to the material editor in Unreal.

210331-2017-08-19-12-10-05-m-wall.png

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