The layer style for the watermark text and watermark image can be different, although the settings to be specified are the same.

Choose the style of your watermark by specifying:
Style: enter the name of an existing style or leave this field blank. Note: if you specify a style that does not exist, the debug window will appear when you try to apply the watermark, but you can continue the script by clicking the play button. Read more on Creating Layer Styles.
Repeats: entering a number greater than zero will cause the watermark to be repeated across the image. The first instance will be positioned according to the position field. Subsequent repeats will be move by the values of the x and y offsets. Here's an image with a repeated watermark.
Rotation: if you wish to have the watermark rotated, enter degrees of rotation from -180 (anti-clockwise) to +180.
Opacity: the layer opacity from 0 to 100%
X/O and Y/O: adjustment in pixels from the selected position. Change X/O from 0 to move the watermark left (negative numbers) or right; change Y/O from 0 to move the watermark up (negative numbers) or down. Tip: there is a Preferences settings - Nudge Pixels - that determines how far the watermark is moved from the edge or corner.
You do need to select a layer style, in which case you may elect to use one of the available blend modes. A layer style will always take precedence over a blend mode choice.