everything i can find on the Strong 4620II points to it being a coolsat sister receiver. with that said i did look at the strong remote and its different than the coolsat remote but i suspect the coolsat remote will run the strong receiver (and only way to find out is to try one)
several can be found on ebay. you also can contact Strong via e-mail and see if they can provide a replacement remote.
the outside apperance & the menu layout on the strong is a close match to the coolsat 4000 & 6000 (most screens seem the same) but without a remote is almost impossible to navigate.
most universal remotes list the units that they will support and not many have found one to work with DVB receivers. There may be a few top of the line universal remotes that will work .....but probably not cost effective replacement.