Here is the problem:
First is my method:
1. Add a new Dynamic Per-Particle Attribute, userScalar1PP, say.
3. Put userScalar1PP into the Export Attributes
4. Connect the particle sampler to the shader ramps, but use the UserScalar1PP attribute instead of age.
Second is Pedro's way - more correct and elegant:
Export both the age and lifespanPP and catch those in two aiUserDataFloat nodes. Then use a Multiply/Divide node and divide the age/lifespanPP. Then pipe that into your shader. This is a much better as it does not require an expensive runtime expression to be cached.
Here is the shader: one ramp for Colour and one for Opacity.
And the answer is yes, you can export any number of attributes, so long as they are seperated by a space in the Export Attribues box.
A sample scene is available in Maya 2014 MA format