Normal mapped sprites: How to disable culling?

We currently have a setup for normal mapped sprites - which allows using light effects in 2d. ( See youtube )

To accomplish this we set up a material using the shader "Standard" with rendering mode "fade", a normal map and the sprite's texture as albedo.
When creating a sprite or animation we simply assign the material instead of the standard sprite material.
Add some lights and your are done.

Everything works fine - scaling - rotating - except when trying to flip the sprite. When flipping twice (e.g. in x and y direction) the sprite comes back...

I guess that the problem is located in the culling that is applied due to the switched orientation of the sprite's vertexes.

I tried to set different values in "Animator" -> "Culling Mode" but that did not change anything.

So my question is: Is there a way to disable culling? Or am I totally wrong and there is there some other reason why the sprites disappear?

 

In the shader you can disable culling by addin Cull Off
http://docs.unity3d.com/Manual/SL-CullAndDepth.html

Can download shader sources from
http://unity3d.com/get-unity/download/archive

And add line: (attached quick test, just added it inside the first subshader part)
Cull Off

 

Thanks - ok - that's now 50% ;-)
The sprite appears again - but the light's direction is now inverted...

Guess inverting the vectors from the normal map would be required now. However unity's shader sources are quite extensive...

In case you have some time it would be great if you could help me out with this... does not have to be for free btw.

 

Initial search suggests that it might be not as easy at it seems:
http://forum.unity3d.com/threads/backface-culling-in-unity.48919/#post-310871
http://forum.unity3d.com/threads/diffuse-no-cull.24580/#post-163735

Have tested any of those sprite light plugin shaders?
(SpriteLamp and some others, if they have solved this)

 

I've tried several - but none of them seems to work as expected... they either did not care about culling - or deliver bad quality - or both...

 

Oh, shoot, I wish I had seen this post sooner! I know it's old, but since Andreas makes nice software that I like, I figured I should send this his way, if it will help. I made this shader a few months ago. It's not my greatest shader in history, but it seems to do the job:

https://bitbucket.org/snippets/HiddenAchievement/rjkkR

Unfortunately, after I came up with that, my artist told me he needed a working emissive layer. Some days, you just can't catch a break!