Hi Paco,
Yes. Use Serial.print(lookupTable [ i ] , HEX) or Serial.print(lookupTable [ i ] , DEC);
The whole 256 set of 8-bit characters includes control characters and other unprintable ones.
In general you don't put binary data into a string since any 0 will terminate it at that point.
You can put a space or return after each 2-digit hex or decimal number to help you read each one
on the VB pc side and, with a loop, put that number into an array of chars again.
Best,
Mitch