You have two (2) options:
1 ) Create a constraint at the nodes in the TX, TY and TZ directions and apply an enforced displacement load to those same nodes.
2) With Femap v11.4 and later, you can assign a Non-Zero Constraint.
Non-zero constraints are contained in a Constraint Set, not Load Sets.
I miss understood the meaning.. We used SPCD cards in the past for enforced displacement, which the drive node/grid had to be SPC inaddition to SPCD. SPC used the SPC SET and the SPCD the LOAD SET. I forgot about the SPC having a value being assigned for displacement. Your right in the case of a pure SPC enforced displacement a SPC would show up in the SPC SET.