[plt-scheme] hash_table_set

Hi there,

I am playing around with hashtables in an extension. From the docs:

 > void scheme_hash_set(Scheme_Hash_Table *table, Scheme_Object *key, 
Scheme_Object *val)
 > Sets the current value for key in table to val. If val is NULL, the 
key is unmapped in table.

But this:

   Scheme_Hash_Table* myStore = scheme_make_hash_table(SCHEME_hash_ptr);
   Scheme_Object *p = scheme_make_integer(12);
   scheme_hash_set(myStore,p,scheme_make_integer(1));
   scheme_hash_set(myStore,p,NULL);
   assert (myStore->count == 0);

fails (myStore->count is 1)

Am I missing something here? My goal is to remove p from the list of keys.

Thanks in advance,
-pp