You can use cross-process memory reference, however in ur case,
ur own process. U can modify the stuffs in your own process
memory space, however, I highly recommend u should just modify
data and not execution code.

But why GW-BASIC and QBASIC can? Coz' u put those codes in
a memory address and u simply just jump to it, those codes has
no interference with BASIC's own executable codes or methods.

But I doubt you can't do it, it's possible, but no one has done it
b4. Remember: U can't modify but add extra codes unless you
know how VB handles those execution codes in low-level.