Adding pause after comas

I use this app to read books. It's great for it. But there is only one problem. I need to add a small pause after comas and I can't figure out how to do it. I tried going to @Voice Settings > Edit speech > replace , to . but it doesn't work.
There is a option to add additional pause at sentence end which I increased to 75 milliseconds. That's why I thought it will work if I transform comas to dots, but it doesn't work. Pls help.

Thank you very much, Greg. It helped. Btw I found 375ms to be the best pause for commas:
Pattern:. ,
Replace:. , <break time="375ms"/>

Also for anyone reading this, the same text in bold doesn't work for me. So be sure to not copy paste bold text to the replace box.