Some questions about the LyX layout

[Julien Hillairet]

Hello,

I'm using a own-written LaTeX class and now I'm writing a LyX layout
in order that the appearance of the LyX document matches the final
.pdf file look.

For that, I've define the following subsection environment:

Style Subsection
        CopyStyle             Section
        LabelCounter          subsection
        TocLevel              2
        LatexName             subsection
        TopSep                0.9
        BottomSep             0.5
        ParSep                0.5
        Font
          Series              Bold
          Size                Large
          Color               Blue
        EndFont
        HTMLTag               h3
End


My questions are:
1) how to define my own color ( {RGB}{54,  95, 145} for example,
instead of "Blue") ?
2) how to underline the text ?


Many thanks in advance,

Best regards,

JH