How to modify a header?
 

I have two questions about modifying a header.

1) On the vBulletin default style, can I remove the vBulletin logo and replace it with just text? Can I just type in "My Forum" and use that in place of a logo? (If so, how would I do that?)

2) If I upload a style or skin from another site (e.g., MinerSkinz or vBSkins), how do I remove the name of the style from the header and how can I put the name of my forum in its place? On this style, for example, how would I delete the word "Officemate" and how would I substitute the name of my forum?