Alternatively, if you want a public roll you can just open the character's sheet and click on the roll you want to happen. It will identify you as the roller as long as you haven't changed your "As" name at the bottom of the chat window. There's an option on the Options page of the sheet (the Cog tab after Core, Bio, and Spells) on the right-hand side to display name in rolls so all rolls made on that sheet will have the character's name displayed in the template when it populates in the chat window, that will make sure it says the roll is from the specific character's sheet.