diff --git a/tv_output.py b/tv_output.py
index 9bc6766..ce63ad8 100644
--- a/tv_output.py
+++ b/tv_output.py
@@ -88,18 +88,44 @@ def tv_option_bytes_rust(name, value, pad):
     else:
         print('%s%s: None,' % (pad, name))
 
+def tv_option_vec_bytes_rust(name, value, pad):
+    if value:
+        print('''%s%s: Some(vec![
+    %s%s
+%s]),''' % (
+            pad,
+            name,
+            pad,
+            chunk(hexlify(value.thing)),
+            pad,
+        ))
+    else:
+        print('%s%s: None,' % (pad, name))
+
 def tv_int_rust(name, value, pad):
     print('%s%s: %d,' % (pad, name, value))
 
-def tv_part_rust(name, value, typ, indent=3):
+def tv_option_int_rust(name, value, pad):
+    if value:
+        print('%s%s: Some(%d),' % (pad, name, value.thing))
+    else:
+        print('%s%s: None,' % (pad, name))
+
+def tv_part_rust(name, value, config, indent=3):
+    if 'rust_fmt' in config:
+        value = config['rust_fmt'](value)
+
     pad = '    ' * indent
-    if type(value) == bytes:
-        if typ == 'Vec<u8>':
-            tv_vec_bytes_rust(name, value, pad)
-        else:
-            tv_bytes_rust(name, value, pad)
-    elif isinstance(value, Some) or value is None:
+    if config['rust_type'] == 'Option<Vec<u8>>':
+        tv_option_vec_bytes_rust(name, value, pad)
+    elif config['rust_type'] == 'Vec<u8>':
+        tv_vec_bytes_rust(name, value, pad)
+    elif config['rust_type'].startswith('Option<['):
         tv_option_bytes_rust(name, value, pad)
+    elif type(value) == bytes:
+        tv_bytes_rust(name, value, pad)
+    elif config['rust_type'].startswith('Option<'):
+        tv_option_int_rust(name, value, pad)
     elif type(value) == int:
         tv_int_rust(name, value, pad)
     else:
@@ -107,7 +133,7 @@ def tv_part_rust(name, value, typ, indent=3):
 
 def tv_rust(filename, parts, vectors):
     print('        struct TestVector {')
-    for p in parts: print('            %s: %s,' % (p[0], p[1]['rust']))
+    for p in parts: print('            %s: %s,' % (p[0], p[1]['rust_type']))
     print('''        };
 
         // From https://github.com/zcash-hackworks/zcash-test-vectors/blob/master/%s.py''' % (
@@ -115,13 +141,13 @@ def tv_rust(filename, parts, vectors):
         ))
     if type(vectors) == type({}):
         print('        let test_vector = TestVector {')
-        for p in parts: tv_part_rust(p[0], vectors[p[0]], p[1]['rust'])
+        for p in parts: tv_part_rust(p[0], vectors[p[0]], p[1])
         print('        };')
     elif type(vectors) == type([]):
         print('        let test_vectors = vec![')
         for vector in vectors:
             print('            TestVector {')
-            for p in parts: tv_part_rust(p[0], vector[p[0]], p[1]['rust'], 4)
+            for p in parts: tv_part_rust(p[0], vector[p[0]], p[1], 4)
             print('            },')
         print('        ];')
     else:
@@ -139,7 +165,7 @@ def render_args():
 
 def render_tv(args, filename, parts, vectors):
     # Convert older format
-    parts = [(p[0], p[1] if type(p[1]) == type({}) else {'rust': p[1]}) for p in parts]
+    parts = [(p[0], p[1] if type(p[1]) == type({}) else {'rust_type': p[1]}) for p in parts]
 
     if args.target == 'rust':
         tv_rust(filename, parts, vectors)
diff --git a/zip_0143.py b/zip_0143.py
index 2ccd578..5d0ffb5 100644
--- a/zip_0143.py
+++ b/zip_0143.py
@@ -8,7 +8,7 @@ from transaction import (
     Script,
     Transaction,
 )
-from tv_output import render_args, render_tv
+from tv_output import render_args, render_tv, Some
 from tv_rand import Rand
 
 
@@ -17,7 +17,7 @@ SIGHASH_NONE = 2
 SIGHASH_SINGLE = 3
 SIGHASH_ANYONECANPAY = 0x80
 
-NOT_AN_INPUT = -1 # For portability of the test vectors
+NOT_AN_INPUT = -1 # For portability of the test vectors; replaced with None for Rust
 
 def getHashPrevouts(tx):
     digest = blake2b(digest_size=32, person=b'ZcashPrevoutHash')
@@ -149,9 +149,12 @@ def main():
         args,
         'zip_0143',
         (
-            ('tx', {'rust': 'Vec<u8>', 'bitcoin_flavoured': False}),
+            ('tx', {'rust_type': 'Vec<u8>', 'bitcoin_flavoured': False}),
             ('script_code', 'Vec<u8>'),
-            ('transparent_input', 'u32'),
+            ('transparent_input', {
+                'rust_type': 'Option<u32>',
+                'rust_fmt': lambda x: None if x == -1 else Some(x),
+                }),
             ('hash_type', 'u32'),
             ('amount', 'u64'),
             ('consensus_branch_id', 'u32'),