In a mesh enabled viewer such as Firestorm, you use the option Avatar / Upload / Mesh Model, then you need to select your upload options on the Upload Model Screen. On the Level of detail tab, select the dae file and set the level of detail such as in this example:http://i.imgur.com/tPmejfk.png
Set the physics on the physics tab, such as what I have in this example:http://i.imgur.com/1P60FCD.png
And the scale in the Upload Options tab:http://i.imgur.com/O41R3bp.png
Then click the calculate weights and fees button, wait for a bit (it can take a while) and when it appears, click the upload button.
Reiterating though - you cannot use Imprudence or a non mesh enabled viewer, they dont have the upload option and you cant even view mesh in imprudence.