I exported a mesh sequence from Realflow to Houdini and imported it as ABC sequence. In Realfow's Export Central, I checked all the channels (velocity, vorticity etc.) for the Mesh and now I was wondering howto access those from inside Houdini.

Inside the Alembicarchive, there is a Mesh Shape SOP in which resides a Alembic Surface node, having that node selected in Details View I cannot see any attributes, even thogh in the Attributes tab I say * for any of the categories… Any idea what I might be missing?

Check out the Python alembic extensions:
http://www.sidefx.com/docs/houdini12.5/hom/abc_extensions [sidefx.com]

In particular you want the function alembicArbGeometry.

What I've done is use an attribCreate node with python expressions to grab the abc attributes I want to apply them to the geometry.