How to provide a comment to SendOrder with Expert?

 
I provide my custom comment to SendOrder() function, but when an order appears in Account History, it says in Comment "#12345, Placed by Expert". Do I need to change some other settings to make a custom comment to appear in there?
 
I think that what you are describing is what you get if you hover the cursor over the ticket number. To show order comments, right click on the headings and click "Comments"
 
tfoller:
I provide my custom comment to SendOrder() function, but when an order appears in Account History, it says in Comment "#12345, Placed by Expert". Do I need to change some other settings to make a custom comment to appear in there?

You seem to be describing the hover-over tooltip which is displayed by MT4. That isn't the same as the order comment

You can make the comments visible in the list by right-clicking over it and ticking Comments on the pop-up menu. 

 
tfoller: I provide my custom comment to SendOrder() function,
brokers can change comments, including complete replacement.
 

Yes, I was describing the tooltip, sorry for the confusion, when I enable Comment column, it says [tp] or [sl], not my comment still.

Is it the broker changing it?

 
tfoller: Yes, I was describing the tooltip, sorry for the confusion, when I enable Comment column, it says [tp] or [sl], not my comment still. Is it the broker changing it?
Yes, and WHRoeder has already stated that. Please read his post and the links he has provided.