#11 Imposrt a symbol that start with numbers

Hi,
I want use a symbol like this:
ImageSet=320x240
but when the list of Symbols is displayed by Antenna it is trunked:
ImageSet=320
I have seen that if the same string start with a char it works:
ImageSet=a320x240
is
ImageSet=a320x240

Can't I use symbols like that?
Thanks