No...not unless it's an act devoid of faith... that is, a friend of the Catholic family asks the Protestand minister friend in attenadance out of respect to the family, to hold the 'towel' or some such outside of being involved in the ceremony. If the Protestand pastor (at least in my denomination here in the U.S.) assisted in 'blessing' the infant baptism, it would be toatally outside of his and his denominations beliefs concerning such acts...
I do believe though, that it depends entirely on the denomination. Here, many Lutherans and Episcopalians would not have a problem with it...