Hi,
I just found that the omxMnor returns a value for an input involving a non p.d. covariance matrix.
Example
omxMnor(array(1,dim=c(2,2)),cbind(0,0),cbind(-Inf,-Inf),cbind(0,0))
returns a value of .375. The limiting value should be .5
S<-diag(1,2);
S[1,2]<-S[2,1]<-2
omxMnor(S,cbind(0,0),cbind(-Inf,-Inf),cbind(0,0))
returns a value of 0.4262082, though S is not p.d.