URLEncode troubles, thinking base64

I have a problem working with unicode text in winDev and PHP.
winDev’s RTF text editor sends HTML version of the text to the server via HTTP Post.

Encoding used in winDev are are: URLEncode and Base64 for the data. I am composing Russian and French texts in winDev editor inerface.

But there are still troubles that the characters remain, like: &engrave;, causing the letter ‘&’ to split the data into multiple keys. Like:


...
[engrave] = '''
..

How to create a binary safe Unicode data transfer?
URLEncode and Base64 encode in winDev do not seem to be solutions; PHP still cannot access the data correctly.

I look forward to find a good solution.