SAC PDF Export file name start with number

Hello Community,

is it somehow possible to start file names for an analytic application export to pdf with numbers? We need to save the pdf's starting with the material number, but SAC does not allow this.

ExportToPDF_1.setFileName(InputField_1.getValue() + "_mat); for example gives the error "Please use a letter as the first character".

Any workarounds known?

Thanks

Christian