How to perform point integrals?

Hello,

I am trying to compute some point integral, which works with linear elements, but not with quadratic, as I am getting the following error:

*** Error: Unable to assemble form over vertices.
*** Reason: Expecting test and trial spaces to only have dofs on vertices for point integrals.
*** Where: This error was encountered inside Assembler.cpp.

Is there a way to perform a point integral with quadratic elements? Is the limitation technical or fundamental? Thank you for any insight.

Martin