Sure, per John's instructions, I added the following stanza (unfortunately I don't know how John preserves the indents)
mesh-table
{
  default
  {
    mesh                                "gp38undec_body/gp38undec_body.im"
    auto-create                         1
  }
}
EDIT: Oops, I was not at the end of the thread when I posted. Hope things worked out.