Normal decimal to hexadecimal function dechex() doesn't work for a number when its slightly large. For those cases the function base_convert() is useful.
print base_convert(time().'000', 10, 16);
You are not the first one who is facing a problem. That's why I always share the solution of problems on my blog those I have faced. I believe someone will find that solution helpful. As I am a programmer, I use to do freelancing more or less and I encounter lot of technical problems when I work. I simply write up those as an article here. I have also placed Google Ads on my blog, so that I can convert my visitors into money. Its not a big amount, but still something is better than nothing.