It's a special format conversion in your application and there's no builtin function in LoadRunner to deal with it. You are supposed to write your own code to translate it (unfortunately, it can't be utlized by loadrunner automation correlation scan).
The translation function should be simple. In your case, the \x8D is the leading boundary, and "_\x1B" is the termination boundary. The characters between them is a hex value. You can parse them to a int value than format to a string using DEC.
For the example below, the characthers between boundary is \x13\xA0\xFD- , here "-" is \x2D in ASCII value. The whole value is \x13\xA0\xFD\x2D. It represents a value of "2DFDA013", and it's DEC format is 771596307
Server sends a value \x8D\x13\xA0\xFD-_\x1B
It is used in further requests as 771596307
BTW, It's recommended to start a new topic for new question. New question in reply of old topic might be neglected.