apply transparent png, material color shine through

I want to do the following:
I have some cubes made by script from a prefab. I assigned a material to them with green color. now i want to assign a png textuure on top so that there is still ggreen color, were there is no picture (transparent spaces.)Is there a possibility to achive that? At the moment I have black color where there should be transparency ans the picture is colored green. I have the standard properties of the material. If I change to a transparent material i get a cutout. :((
Any ideas?

you just need to make a one geometry (little smaller to draw behind texture) with solid diffuse green color and the second one with transparency shader and your texture attached

the best way is to write own shader, it’s will be a very simple shader. better to take one that can do everyting you want but havn’t a color at write 2-3 rows to it with multiply by Color. may be “Transparent/Diffues” or “Transparent/Cutout/Diffuse”?

Shader "Diffuse colored in alpha"
		_Color ("Main Color", Color) = (1,1,1,1)
		_MainTex ("Base (RGBA)", 2D) = "white" {}
		Tags { "RenderType"="Opaque" }
		LOD 250
		#pragma surface surf Lambert

		sampler2D _MainTex;
		fixed4 _Color;

		struct Input
			float2 uv_MainTex;
			float2 uv_DecalTex;

		void surf (Input IN, inout SurfaceOutput o)
			fixed4 c = tex2D(_MainTex, IN.uv_MainTex);
			o.Albedo = lerp(_Color, c.rgb, c.a);
			o.Alpha = 1;
	Fallback "Diffuse"

OK, thank you very much - doesn’t look that compicated. I will try it out!