A Lot Multiplier of copying signals

I need a lot multiplier when copying signals. When the account copies the signal with the volume MetaTrader4 calculated (like 0.1lot), the EA sends a totally same order that "multiplies" the signal's order. There is a similar example on the forum, https://www.mql5.com/en/market/product/16813, https://www.mql5.com/en/articles/2438, but it is on MQL5 platform, unfortunately. Can anyone help me to accomplish the same function on MQL4? Thanks a lot.