You do need the INIT-BY-TYPE directive but unfortunately it is a new directive that will only be available as of Visual COBOL 2.2 update 1 which will be released at the beginning of June so it is not supported in the version that you are currently using.
Currently we have support for the DEFAULT-BYTE directive which allows you to specify a single character value to which all of working-storage will be initialized.
If you used DEFAULT-BYTE"48" all of your fields would be initialized to zeroes which would be fine for numerics but probably isn't what you want for pic x fields.
If you used DEFAULT-BYTE"32" then all of your fields would be initialized to spaces which might be ok if you also set the directive SPZERO on which causes spaces in numerics to be treated as though they were zeroes.
This might be your best bet, other than using an INITIALIZE statement or VALUE clause to explicitly initialize your data, al least until 2.2 update 1 becomes available.
Thanks.