'Split infinitives' are OK, and the editor needs to go back to school, IMHO. Those who have a broad objection to mid-position adverbs might need a little brushup course too, IMHO. The compulsive location of adverbs before any auxiliary verbs appears to be an American peculiarity: see, e.g., Swan's "Practical English Usage", 2nd ed., p. 24. -- Doug Wilson