Help with column formula in radiotable

[Thorsten Grothe <info@th-grothe.de>]

Hello,

I would like to assign a relative column formular for the 6 column (name 
= BIPr).

The formular should start in the *second field* of column 3 (value = 12) 
and multiply it with *first value of column* 4 (value = 2.8) etc. like this:

12 * 2.8
4 * 0.7
...

|---+------+-------+-------+-------+-------+---|
| ! | Jahr | Menge | Preis |  BIPn |  BIPr | W |
|---+------+-------+-------+-------+-------+---|
| # |    1 |    10 |   2.8 | 28.00 |     0 |   |
| # |    2 |    12 |   0.7 |  8.40 |       |   |
| # |    3 |     4 |  4.00 | 16.00 |       |   |
|---+------+-------+-------+-------+-------+---|
| _ |      |       |       |  suma |  sumb |   |
|   |      |       |       | 52.40 | 16.00 |   |

How can I do this?

Thanks in advance for your help!!

Regards
Thorsten Grothe