How to add transparency / alpha color to an existing addon

[p6kocka]

How to add alpha to exisitng addon with editable colors?
It looks like this:

type = "colorpicker",
name = "No Target Colour",
getFunc = function() return RAEIH.HexToRGB(RAEIH.SavedVars.ReticleRCNoTarget) end,
setFunc = function(r, g, b) RAEIH.SavedVars.ReticleRCNoTarget = RAEIH.RGBToHex(r, g, b)
RAEIH.SetReticle()
RAEIH.FormatReticle() end,
width = "n",
default =
{
r = RAEIH.HexToR(RAEIH.DefaultSavedVars.ReticleRCNoTarget),
g = RAEIH.HexToG(RAEIH.DefaultSavedVars.ReticleRCNoTarget),
b = RAEIH.HexToB(RAEIH.DefaultSavedVars.ReticleRCNoTarget)

I just want to to set alpha to 0 for this reticle with no target. Just to disable reticle in this case.