Hi there,
If the terms below are not familiar to you, check:
http://en.wikipedia.org/wiki/Ornament_%28music%29
The first thing to say is that the grace note needs to be "independent", which means that it doesn't form part of the beat count in a bar. So, to create a acciaccatura use:
Attributes > Independent Grace Note
or, to create an appoggiatura, use
Attributes > Independent
The acciaccatura is automatically stem up and the appogiatura conforms to position on the stave and layer. You can change either of these by using:
Atttributes > Stems
The acciaccatura creates a slur automatically while the appoggiatura doesn't - you have to add your own.
Sorry - got to run now (England football match this afternoon and have to go and get beers in) so can't do slurs now. I'll try and remember to pop by later.
Pete