You can do this by using insert.field.equations and formulas.
advance.options
This will position the next character anywhere you want! Problem is that you
need to carefully restore the correct cursor position after your 'double
character'. If you need this frequently (as I do) then once you get it
right, put it into a macro and assign a key to it for your convenience, or
put a button on a toolbar to call it.
OR
If it's just the m-dot combination that you need, then use Microsoft
equation which has a built in template for your needs. You may need to
select the non-italic character font
Phil
[yes, I too remember doing that in WP5.1! ... which, at the time, seemed to
me to be the endpoint in the evolution of word-processing]