Export Caracters problem

Hi,

I have a problem with export my gantt to Excel.
I using api.js with this settings:

gantt.exportToExcel({ name:"mygantt.xlsx", header:"<h1>My company</h1>", footer:"<h4>Bottom line</h4>", locale:"pt" });

But excel file, export incorrect unicode format:

Somebody help me to solve this problem ?

TY