Camera.RenderWithShader + Post Processing Stack V2

Hey everyone !
I'd like to improve an old image effect, using Post Processing Stack V2
Here's my old implementation :

Code (CSharp):

1. var temp = cam.targetTexture = RenderTexture.GetTemporary(cam.pixelWidth, cam.pixelHeight,24,RenderTextureFormat.ARGB32);
2. cam.targetTexture.Create ();
3. cam.RenderWithShader (shader,"");

And the new code :

Code (CSharp):

1. public override void Render(PostProcessRenderContext context)
2.         {
3.  
4.             ...
5.             // Can I create a custom render pass in here ?
6.             context.GetScreenSpaceTemporaryRT(cmd, rt1, 0, context.sourceFormat, RenderTextureReadWrite.Default, FilterMode.Bilinear);
7.             cmd.BlitFullscreenTriangle(context.source, rt1, sheet, 0);
8.  
9.            ...
10.         }

it basically create a temporary cam, which is not ideal. I'd like to find a way to make my custom pass by rendering my objects with a shader, then passing that to my image effect shader.