Use Caption to specify the text string that appears on the button. 

The Caption portion of a command link button is typically displayed in a larger font than the rest of the user interface and also a regular button control. The font color used for the caption text is also different. 

To underline a character in a Caption that appears on the button, include an ampersand (&) before the character. This type of character is called an accelerator character. The user can then select the button by pressing Alt while typing the underlined character. To display an ampersand character in the caption, use two ampersands (&&).

TJSCustomCommandLinkButton Properties