CCl: Gaussian and Field keyword and Optimizations



 Hi --
 I'm trying to optimize a molecule in the presence of a field using
 Gaussian.  Why is it that Gaussian won't allow me to optimize using
 PM3?  But it seems to let me optimize in the presence of a field with
 HF?
 In light of the fact that Gaussian won't let me optimize in the presence
 of a field with PM3.  Does that mean that a single point calculation
 with PM3 and in the presence of a Field also has no meaning????!!!
 Thanks! :)
 Connie