My Polar F4 does not ask for exercise type, merely calculates burn based on HR and my inputted stats.
However, I do want to point out, that using 1lb hand weights is generally unsafe. Also, the point of warming up is to slowly build up to your target HR, not to get there quickly. If you just want to leap there quickly just do jumping jacks. You'll be at target HR within a minute. But that's not really an appropriate warmup.
Walking with hand weights: www.sparkpeople.com/community/ask_the_expe