Using EffectComposer with shader that has two outputs

Questions
,
1

Are shaders with two outputs are supported by the EffectComposer (background: i need to pass 5 floats to the second shader).

I create a render target with count set to two:

var renderTarget = new WebGLRenderTarget(  w, h, { type: FloatType, count:2 } );

The first shader has two outputs declared like this:

layout(location = 0) out vec4 gxray;
layout(location = 1) out vec4 gmask;

For the ShaderPass I can set only one textureID as input:

shaderPass2 = new ShaderPass(shader2, "tInput", null, material2)

I tried this without success:

shaderPass2.uniforms["tInput"] = renderTarget.textures[ 0 ]  
shaderPass2.uniforms["tInput2"] = renderTarget.textures[ 1 ]

Is this possible or should I try implementing this without EffectComposer?

The error/warning I always get:

GL_INVALID_OPERATION: Active draw buffers with missing fragment shader outputs.
2

How are you controlling effectcomposer so that it binds your multitarget for output?

it sounds like its trying to output to its regular framebuffer setup.

This sounds complex enough that it might be easier to get it working outside of effectscomposer first, then perhaps convert it, if you can get it to work.