How to extend SAnimationGraphNode (link Errors)

Does anyone know how to extend SAnimationGraphNode ?
im trying to create a widget control on my custom node.
Custom animation sequence node and graph node works perfectly, the issue is with SAnimationGraphNode when i try to contruct the actual widget.

/* CPP File */

//     Adapted from SGraphNodeSequencePlayer
#include "Animation/SGraphNode_CustomNode.h"

//	Engine
#include "Widgets/Input/SSlider.h"
#include "Animation/AnimBlueprintGeneratedClass.h"
#include "Kismet2/KismetDebugUtilities.h"
#include "Kismet2/BlueprintEditorUtils.h"

//	Custom Graph Node extended from UAnimGraphNode_AssetPlayerBase
#include "Animation/AnimGraphNode_CustomNode.h" 

//     Custom Anim Node extended from FAnimNode_AssetPlayerBase
#include "Animation/AnimCustomNode.h"

void SGraphNode_CustomNode::Construct(const FArguments& InArgs, UAnimGraphNode_Base* InNode)
{
	this->GraphNode = InNode;
	this->SetCursor(EMouseCursor::CardinalCross);
	this->UpdateGraphNode();

        // Commenting this line it does compile (but, with no widget on node)
	SAnimationGraphNode::Construct(SAnimationGraphNode::FArguments(), InNode);
}

// Header File

#pragma once

#include "CoreMinimal.h"
#include "Layout/Visibility.h"
#include "Widgets/DeclarativeSyntaxSupport.h"
#include "SNodePanel.h"

//   original include line of SAnimationGraphNode from SGraphNodeSequencePlayer.h does not work ("can not open source file..." intellisense error)
//#include "AnimationNodes/SAnimationGraphNode.h"

//    needs to be the full line direction
#include "Editor/AnimationBlueprintEditor/Private/AnimationNodes/SAnimationGraphNode.h"

class SVerticalBox;
class UAnimGraphNode_Base;
struct FAnimCustomNode;
struct FGraphInformationPopupInfo;

class SGraphNode_CustomNode : public SAnimationGraphNode
{
public:

	SLATE_BEGIN_ARGS(SGraphNode_CustomNode) {}
	SLATE_END_ARGS()

	void Construct(const FArguments& InArgs, UAnimGraphNode_Base* InNode);

        // SNodePanel::SNode interface
	virtual void GetNodeInfoPopups(FNodeInfoContext* Context, 
        TArray<FGraphInformationPopupInfo>& Popups) const override;
	// End of SNodePanel::SNode interface

      . . .
}

custom editor module build file :

using UnrealBuildTool;

public class CoopGameEditor : ModuleRules
{
	public CoopGameEditor(ReadOnlyTargetRules Target) : base(Target)
	{
        PCHUsage = PCHUsageMode.UseExplicitOrSharedPCHs;

        PublicIncludePaths.Add("CoopGameEditor/Public");
		PrivateIncludePaths.Add("CoopGameEditor/Private");
		
		PublicDependencyModuleNames.AddRange
		(
			new string[] 
			{
                "Core",
                "CoreUObject",
                "Engine",
                "InputCore",
                "AnimationCore",
                "AnimGraphRuntime", /* Engine Nodes */
                "BlueprintGraph",
                "CoopGame"
            }
		);
		
		PrivateDependencyModuleNames.AddRange
		(
			new string[] 
			{
				"UnrealEd",
                "GraphEditor",
                "AnimGraph",
                "AnimationBlueprintEditor",
                "PropertyEditor",
                "EditorStyle",
                "Slate",
                "SlateCore"
            }
		);

        PrivateIncludePathModuleNames.AddRange(new string[] { });
        DynamicallyLoadedModuleNames.AddRange(new string[] { });
    }
}

Error Output:

1>SGraphNode_CustomNode.cpp.obj : error LNK2019: unresolved external symbol "public: void __cdecl SAnimationGraphNode::Construct(struct SAnimationGraphNode::FArguments const &,class UAnimGraphNode_Base *)" (?Construct@SAnimationGraphNode@@QEAAXAEBUFArguments@1@PEAVUAnimGraphNode_Base@@@Z) referenced in function "public: void __cdecl SGraphNode_CustomNode::Construct(struct SGraphNode_CustomNode::FArguments const &,class UAnimGraphNode_Base *)" (?Construct@SGraphNode_CustomNode@@QEAAXAEBUFArguments@1@PEAVUAnimGraphNode_Base@@@Z)