ECDSA with SHA256 and sepc192r1 curve: Impossible, or how to calculate $e$?
NIST FIPS 186-4 at the end of section 6.4 states that:


  When the length of the output of the hash function is greater than the
  bit length of $n$, then the leftmost $n$ bits of the hash function output
  block shall be used in any calculation using the hash function output
  during the generation or verification of a digital signature.


In section 6.1 they define $n$ as the order of the generator, which makes the wording


  leftmost $n$ bits


wrong. Although it's clear they meant the bit size of $n$.

Which means:


You don't need a bigger curve
BouncyCastle implementation looks correct