According to some authors, it is built in A.A.Beilinson "Higher regulator of modular curves" a class $\mathbf{Eis}_{\phi}$ in the motivic cohomology of the modular curve where $\phi$ is a Schwartz function over the finite adeles. Since the modular curve is only quasi-projective, I assume it is mixed-motivic cohomology? I am right ?
I say "according to some authors" because I haven't read this article by Beilinson (I can't find it anywhere). This document is a bit old and sometimes Beilinson is hard to read so my question is
Does anyone know of a reference where this construction is done with the technical details? If not how can I find this article of Beilinson?