Formatting of @sc may involve uppercasing the argument.
The specification of @-command argument uppercasing can be changed with
texinfo_register_upper_case_command:
$command_name is the @-command name, without the leading @. $value sets or unsets uppercasing of argument.
For example, to prevent @sc argument from being uppercased and set
@var argument to be uppercased:
texinfo_register_upper_case_command('sc', 0);
texinfo_register_upper_case_command('var', 1);