Macros, VBA, Visual Basic are not handled by SpreadsheetConverter, only Excel formulas and about 300 Excel functions.
However, if you can translate these functions yourself, the generated code can call them.
In the spreadsheet udf_toy.xls you can see the signature of the 3 functions that can be user-defined. The functions will be called each time a recalculation is triggered.
It is just 3 functions. If you need more than 3 functions, you can for use the first string argument to send the name of the function, and have a switch first in your code.
You have to insert the definitions manually into the SpreadsheetConverter generated source files