Is it possible to sample an input texture in a Direct2D vertex shader?

[RevDrSquash]

I am trying to sample from an input texture in a vertex shader in a Direct2D effect that distorts the image by shifting vertices based on vectors stored in the input texture. However, whenever I try to sample from an input texture in my vertex shader the sampling function returns 0.

I haven't been able to find anything suggesting that this is definitively possible or impossible so that's my main question.

There are several examples of doing this in Direct3D but I would rather use Direct2D exclusively if possible. Sample code would obviously be appreciated. If this turns out to be possible and I'm doing something wrong I'll post my code.

[JagerDesu]

What code have you written so far?

[RevDrSquash]

This is what I'm trying to use in my vertex shader:

    float2 ret;
    ret.x = input.meshPosition.x * sceneToInput0X[0] + sceneToInput0X[1];
    ret.y = input.meshPosition.y * sceneToInput0Y[0] + sceneToInput0Y[1];
    float4 offset = InputTexture.SampleLevel(Sampler, ret, 0);

The problem is that offset is always a zero vector. The best explanation I can find is that the input texture isn't bound to the vertex shader, only the pixel shader. Direct3D has a way to bind a texture to a vertex shader (VSSetShaderResources) but I can't find anything similar in Direct2D.